The race for the Champions Cup knockout stages hots up this weekend as some teams attempt to clinch home quarter-finals while others battle to remain in contention.
Leinster are the only team to have already secured a spot in the last eight and 11 teams still stand a chance of joining them, including defending champions Saracens.
There are crucial games in all five pools as the road to Marseille intensifies…
Pool 1: Saints seek response
The heavy losses to Leinster in December's back to backs threatened to derail Northampton's season but their response has been impressive.
Successive Premiership wins have kept them on the coattails of league leaders Exeter and they could still reach the Champions Cup quarters by winning their final two pool matches.
Northampton were controversial winners away to Benetton in round two, Dan Biggar's last-gasp penalty snatching a 35-32 victory, and they meet again at Franklin's Gardens.
The Italians are more competitive in Europe this season compared to previous campaigns, but Saints should still be targeting a bonus-point win.
Pool leaders Leinster remain in unstoppable form and maintained their 100 start to the season with three derby wins during the festive season. With Lyon's interest in the competition long over, the four-time winners should move a step closer to a home quarter-final.
Northampton: 15 George Furbank, 14 Harry Mallinder, 13 Fraser Dingwall, 12 Rory Hutchinson, 11 Taqele Naiyaravoro, 10 James Grayson, 9 Henry Taylor; 1 Francois van Wyk, 2 Sam Matavesi, 3 Paul Hill, 4 Api Ratuniyarawa, 5 David Ribbans, 6 Courtney Lawes, 7 Lewis Ludlam, 8 Teimana Harrison (c).
Replacements: 16 James Fish, 17 Ben Franks, 18 Owen Franks, 19 Alex Coles, 20 Mitch Eadie, 21 Cobus Reinach, 22 Andy Symons, 23 Ollie Sleightholme.
Benetton Rugby: 15 Jayden Hayward, 14 Leonardo Sarto, 13 Tommaso Benvenuti, 12 Alberto Sgarbi (c), 11 Monty Ioane, 10 Tommy Allan, 9 Dewaldt Duvenage; 1 Nicola Quaglio, 2 Hame Faiva, 3 Tiziano Pasquali, 4 Alessandro Zanni, 5 Federico Ruzza, 6 Marco Lazzaroni, 7 Giovanni Pettinelli, 8 Marco Barbini.
Replacements: 16 Engjel Makelara, 17 Federico Zani, 18 Cherif Traore, 19 Eli Snyman, 20 Marco Fuser, 21 Charly Trussardi, 22 Antonio Rizzi, 23 Marco Zanon.
Pool 2: Glasgow great returns
The stakes couldn't be higher for Glasgow on Stuart Hogg's return to Scotstoun. Beat Exeter and they travel to Sale in round six with all to play for. Lose and their Champions Cup campaign is dead and buried.
Hogg was a tryscorer when these sides last met at Scotstoun in 2018. He crossed after two minutes and the Warriors went onto win 28-21. Could Jonny Gray repeat the trick ahead of his switch to Sandy Park?
The Chiefs are on an eight-game winning streak and have taken both the Premiership and Europe by storm this season. They are four wins from four in the latter and a first home quarter-final is within reach.
Glasgow have struggled for consistency this season, claiming an impressive win at La Rochelle in round three only to lose at home to the same opponents a week later. That disappointing reverse leaves them with a point to prove.
Glasgow Warriors: 15 Glenn Bryce, 14 Tommy Seymour, 13 Huw Jones, 12 Samuel Johnson, 11 Kyle Steyn, 10 Adam Hastings, 9 George Horne; 1 Oli Kebble, 2 Fraser Brown, 3 Zander Fagerson, 4 Scott Cummings, 5 Jonny Gray, 6 Ryan Wilson, 7 Callum Gibbins (c), 8 Matt Fagerson.
Replacements: 16 George Turner, 17 Aki Seiuli, 18 Adam Nicol, 19 Robert Harley, 20 Chris Fusaro, 21 Ali Price, 22 Peter Horne, 23 Niko Matawalu.
Exeter Chiefs: 15 Stuart Hogg, 14 Jack Nowell, 13 Ian Whitten, 12 Ollie Devoto, 11 Olly Woodburn, 10 Joe Simmonds (c), 9 Nic White; 1 Alec Hepburn, 2 Luke Cowan-Dickie, , 4 Jannes Kirsten, 5 Sean Lonsdale, 6 Dave Ewers, 7 Jacques Vermeulen, 8 Matt Kvesic.
Replacements: 16 Elvis Taione, 17 Ben Moon, 18 Marcus Street, 19 Will Witty, 20 Don Armand, 21 Jack Maunder, 22 Gareth Steenson, 23 Sam Hill.
Pool 3: Top two set for shootout
Unless Bath or Harlequins spring a major upset in round six, both Clermont Auvergne and Ulster will progress to the Champions Cup quarter-finals.
The question is who takes top spot. And that will be answered on Saturday when they collide at Stade Marcel Michelin.
John Cooney inspired Ulster to an 18-13 win over Clermont in Belfast last November and the scrum-half has remained in red-hot form, sparking calls for him to be handed the No 9 jersey for Ireland's Six Nations opener.
Ulster have claimed some excellent results this season and tore Munster apart in their last outing, but a victory in the Massif Central would rank as their best yet.
While flaky on the road, Clermont are a serious force on home soil. They have won their last six matches at Michelin and racked up a half-century of points in both Champions Cup home games against Harlequins and Bath.
Clermont Auvergne: 15 Nick Abendanon, 14 Damian Penaud, 13 Isaiah Toeava, 12 George Moala, 11 Alivereti Raka, 10 Camille Lopez, 9 Morgan Parra (c); 1 Etienne Falgoux, 2 John Ulugia, 3 Rabah Slimani, 4 Paul Jedrasiak, 5 Sébastien Vahaamahina, 6 Arthur Iturria, 7 Alexandre Lapandry, 8 Fritz Lee.
Replacements: 16 Yohan Beheregaray, 17 Loni Uhila, 18 Sipili Falatea, 19 Sitaleki Timani, 20 Alexandre Fischer, 21 Greig Laidlaw, 22 Jake McIntyre, 23 Apisai Naqalevu
Ulster Rugby: 15 Will Addison, 14 Rob Baloucoune, 13 Luke Marshall, 12 Stuart McCloskey, 11 Jacob Stockdale, 10 Billy Burns, 9 John Cooney; 1 Jack McGrath, 2 Rob Herring, 3 Marty Moore, 4 Alan O'Connor, 5 Iain Henderson (c), 6 Sean Reidy, 7 Jordi Murphy, 8 Marcell Coetzee.
Replacements: 16 Adam McBurney, 17 Eric O'Sullivan, 18 Tom O'Toole, 19 Kieran Treadwell, 20 Matt Rea, 21 David Shanahan, 22 Bill Johnston, 23 Matt Faddes.
Pool 4: Saracens still in the hunt
With all their off-field problems it is easy to forget that Saracens remain in contention for the quarter-finals.
Premiership survival may be north Londoners' priority but victories in their final two pool matches could be enough to clinch one of the best runners-up spots.
First up is Saturday's trip to the struggling Ospreys where a bonus-point win, coupled with a Racing 92 win over Munster the following day, will put Sarries' fate back in their own hands.
Players are expected to depart Allianz Park before the end of the month as the club attempts to trim its wage bill, but the Champions Cup trophy could remain for at least another couple of months.
Ospreys: 15 Dan Evans, 14 Hanno Dirksen, 13 George North, 12 Tiaan Thomas-Wheeler, 11 Luke Morgan, 10 Luke Price, 9 Shaun Venter; 1 Darryl Marfo, 2 Scott Otten, 3 Ma'afu Fia , 4 Adam Beard, 5 Alun Wyn Jones, 6 Dan Lydiate (c), 7 Sam Cross, 8 Morgan Morris.
Replacements: 16 Sam Parry, 17 Rhys Fawcett, 18 Simon Gardiner, 19 Lloyd Ashley, 20 Dan Baker, 21 Aled Davies, 22 Cai Evans, 23 Lesley Klim.
Saracens: 15 Elliott Obatoyinbo, 14 Sean Maitland, 13 Alex Lozowski, 12 Nick Tompkins, 11 Alex Lewington, 10 Manu Vunipola, 9 Richard Wigglesworth; 1 Rhys Carre, 2 Jack Singleton, 3 Titi Lamositele, 4 Will Skelton, 5 George Kruis, 6 Nick Isiekwe, 7 Calum Clark, 8 Jackson Wray (c).
Replacements: 16 Tom Woolstencroft, 17 Richard Barrington, 18 Vincent Koch, 19 Joel Kpoku, 20 Sean Reffell, 21 Tom Whiteley, 22 Roti Segun, 23 Ali Crossdale.
Munster seek Paris victory
Saracens' win over Munster in round four turned this pool on its head and the Irish province must now win in Paris to stay alive in the competition.
Another injury setback to fly-half Joey Carbery hasn't helped their cause, with JJ Hanrahan starting at 10 despite concerns over his hamstring.
Racing have scored 19 tries in their four pool matches to date and victory over Munster will confirm their place in the last eight.
Racing 92: 15 Brice Dulin, 14 Teddy Thomas, 13 Virimi Vakatawa, 12 Henry Chavancy (c), 11 Juan Imhoff, 10 Finn Russell, 9 Teddy Iribaren; 1 Eddy Ben Arous, 2 Camille Chat, 3 Ben Tameifuna, 4 Boris Palu, 5 Dominic Bird, 6 Wenceslas Lauret, 7 Bernard Le Roux, 8 Antonie Claassen.
Replacements: 16 Teddy Baubigny, 17 Hassane Kolingar, 18 Cedate Gomes Sa, 19 Donnacha Ryan, 20 Fabien Sanconnie, 21 Maxime Machenaud, 22 Ben Volavola, 23 Olivier Klemenczak.
Munster: 15 Mike Haley, 14 Andrew Conway, 13 Chris Farrell, 12 Rory Scannell, 11 Keith Earls, 10 JJ Hanrahan, 9 Conor Murray; 1 Dave Kilcoyne, 2 Niall Scannell, 3 Stephen Archer, 4 Jean Kleyn, 5 Billy Holland, 6 Peter O'Mahony (c), 7 Jack O'Donoghue, 8 CJ Stander.
Replacements: 16 Kevin O'Byrne, 17 Jeremy Loughman, 18 John Ryan, 19 Arno Botha, 20 Chris Cloete, 21 Craig Casey, 22 Dan Goggin, 23 Shane Daly.
Pool 5: Must-win for Connacht, Gloucester
Unless Connacht or Gloucester finish with a flourish there will be only one team progressing from Pool 5 - Toulouse.
Connacht, beset by injury and form after Christmas stuffings against Ulster and Leinster, must beat four-time European champions Toulouse. It's a big test, but one they passed when Toulouse last visited Galway in 2016.
Gloucester's quarter-final hopes are dangling by a thread after their late collapse against Connacht last month, but they can retain a glimmer of hope by beating a Montpellier side whose interest in the tournament is over for another season.
Gloucester: 15 Jason Woodward, 14 Louis Rees-Zammit, 13 Chris Harris, 12 Billy Twelvetrees, 11 Ollie Thorley, 10 Danny Cipriani, 9 Willi Heinz (c); 1 Val Rapava Ruskin, 2 Todd Gleave, 3 Ciaran Knight, 4 Gerbrandt Grobler, 5 Franco Mostert, 6 Ruan Ackermann, 7 Lewis Ludlow, 8 Ben Morgan.
Replacements:16 Henry Walker, 17 Alex Seville, 18 Josh Hohneck, 19 Alex Craig, 20 Freddie Clarke, 21 Joe Simpson, 22 Mark Atkinson, 23 Owen Williams.