The Brazilian converted with a late effort that was helped on its way by the Gunners man past Ospina, as the battle for top spot in the group continues wide open.
Lucas Moura kept Paris Saint-Germain’s chances of finishing top of Champions League Group A alive as his header salvaged a 2-2 draw against Arsenal at the Emirates Stadium.
An Olivier Giroud penalty and an own goal from Marco Verratti had helped Arsenal overturn Edinson Cavani’s deserved opener for PSG and they appeared on course to clinch top spot.
However, Brazil winger Lucas – who had struck the bar with a wonderfully-struck free-kick earlier in the second-half – levelled proceedings with 13 minutes remaining.
A point was the least Unai Emery’s men deserved and Cavani had two gilt-edged opportunities to seal a memorable victory – and top-spot – in the closing stages, but the Uruguayan failed to find the target as both sides had to settle for a point.
PSG consequently go top of the pool due to a superior head-to-head record over Arsene Wenger’s men having scored more away goals in the two contests between the teams.
However, with the sides locked on 11 points apiece the fight for top spot in Group A goes to matchday six.
The visitors made a bright start despite being shorn of several first-team regulars including Angel Di Maria and Serge Aurier – who was forbidden to travel to the UK.
It was Aurier’s replacement Thomas Meunier’s cross that provided Cavani, who netted after 42 seconds in the reverse fixture, with the chance to open the scoring but he just failed to connect.
Kieran Gibbs then cleared off the line after Thiago Silva deflected Cavani’s miscued header goalwards.
PSG had the lead after 18 minutes, though, as Cavani slid in to bundle home Blaise Matuidi’s cross from point-blank range.
Arsenal finally awoke from their slumber and Silva made a great last-ditch challenge to deny Aaron Ramsey.
And the Gunners were gifted a way back into the match just before half-time when Grzegorz Krychowiak scythed down Alexis Sanchez in the area.
Giroud assumed responsibility and sent Alphonse Areola the wrong way with Arsenal’s first attempt on goal.
That goal revitalised Arsenal and the hosts came out strong after the restart, but it was PSG who almost retook the lead.
Lucas earned a free-kick after capitalising on Laurent Koscielny’s slack play and from the resulting free-kick he rattled the woodwork with a venomous strike.
Arsenal upped the tempo, though, and Giroud would have had his second if not for Marquinhos’ crucial intervention.
But they did move in front in fortunate circumstances on the hour. Ramsey’s strike rebounded onto the shins of Verratti and into the back of the net as the midfielder became the first PSG player to score a Champions League own goal.
However, Arsenal could not hold onto their lead and were punished for more sloppy defending when the unmarked Lucas headed in from Hatem Ben Arfa’s corner.
Cavani should have wrapped up the victory in the final 10 minutes, but the former Napoli striker could only direct a tame chip at David Ospina before he directed a close-range header wide from PSG’s next attack as the spoils were shared.