Mesut Ozil grabbed an 87th-minute winner as Arsenal fought back from two goals down against Ludogorets to secure a 3-2 victory and book their place in the last 16 of the Champions League.
The Gunners, who had thrashed the Bulgarians 6-0 a fortnight ago, found themselves 2-0 down inside 15 minutes after goals from Jonathan Cafu (12) and Claudiu Keseru (15).
But they fought back before the break through goals from Granit Xhaka (20) and Olivier Giroud (42), leaving Ozil to snatch all three points with a superb individual goal three minutes from time.
Victory means Arsene Wenger's side have secured qualification through to the knockout stages with two games to spare, but they still face a battle with Paris Saint-Germain for top spot after the Ligue 1 side scored a late winner of their own to beat Basel 2-1.
Arsenal, who have qualified for the last 16 for a 17th consecutive season, take on PSG in their next Champions League fixture on November 23 at the Emirates Stadium but before that attention turns back to the Premier League and Sunday's north London derby against Tottenham.
With the derby in mind, Wenger made five changes to the side that beat Sunderland 4-1 at the weekend, handing Aaron Ramsey and Giroud their first starts since recovering from injury.
The Gunners controlled the ball very early on and created the first chance of the game with Francis Coquelin slipping the ball through to Ozil, but the German's shot was straight at Milan Borjan.
Wenger's side were behind in the 12th minute though after referee Bas Nijhuis handed the hosts a soft free-kick for handball against Xhaka. Ludogorets took full advantage as Cafu got to Wanderson's deep free-kick ahead of Shkodran Mustafi to turn the ball home from close range.
Three minutes later, that 6-0 defeat at the Emirates seemed a distant memory as Wanderson picked out Cafu on the left flank. The goalscorer burst past an isolated Kieran Gibbs before picking Keseru, who finished from close range.
Arsenal responded well though as Ozil pulled the ball back from the byline for Xhaka and the Swiss midfielder's shot found the bottom corner to hand the visitors a lifeline.
Ludogorets were still posing a threat on the counter-attack, but the Gunners were back in the contest and slowly finding their rhythm.
And they were back on level terms just before the break as Ramsey's cross picked out Giroud, who got to the ball ahead of the goalkeeper to flick the ball into the back of the net.
Chances were few and far between in what was an even start to the second-half until Wanderson found his way in behind the Arsenal defence just after the hour-mark, but the Brazilian did not make the most of his opportunity with David Ospina saving bravely at his feet.
Arsenal's best moment came in the 73rd minute as Xhaka looked to play in Alexis Sanchez, but the Chile international's touch let him down as the ball rolled safely through to Borjan.
The game looked to be petering out to a draw until substitute Mohamed Elneny played in Ozil, who showed great composure to lift the ball over goalkeeper before going round two defenders to slide the ball into an empty net to seal victory and Arsenal's spot in the last 16.