Tommy Bell kicked 19 points as London Irish beat Yorkshire Carnegie 29-18 on Wednesday to take a giant step towards regaining their Premiership status.
The full-back booted five penalties and two conversions at Headingley to help the Exiles assume a strong position ahead of next Wednesday's play-off final second leg at the Madejski Stadium.
Both sides touched down twice, with Danny Hobbs-Awoyemi and Fergus Mulchrone going over for Irish, while Jonah Holmes and Mike Mayhew grabbed tries for Carnegie.
The visitors scored the opening try on 13 minutes when scrum-half Brendan McKibbin set up Hobbs-Awoyemi to leave a huge gap in the home defence as the prop ran 20 yards to the line.
However, the home side reacted quickly as Richard Mayhew powered away from a line-out before feeding hooker Mike Mayhew, who reduced the deficit to five points.
And nine minutes later, the hosts took the lead with a brilliant try, as centres Pete Lucock and Tom Casson combined to create an opportunity for winger Holmes.
Joe Ford's conversion gave Carnegie a deserved 15-13 advantage at the break, before the second half belonged to Irish.
Following a period of prolonged pressure, Alex Lewington set up a try for Mulchrone, which Bell converted with a superb touchline kick.
With just two points separating the teams going into the final quarter-of-an-hour, three more Bell penalties gave the Reading-based team a decisive margin ahead of their home leg next week.