Jefferson Farfan then grabbed the equaliser and, although both sides had chances to win it, the scores remained level as both parties remain in the qualifying spots in Group B.
Here, Sports Mole dissects the Gunners' 2-2 draw.
On target 7
On target 5
Was the result fair?
Yes, a draw was probably the fairest result. Schalke performed better than Arsenal but failed to create enough chances, while Arsenal could have won it right at the death through Walcott. Schalke certainly didn't deserve to lose and did well to overturn the two goal deficit and rescue a point.
Schalke will be pleased with their performance, although they probably went into the game thinking that they could walk away with all three points. They struggled to break Arsenal down at times, but having gone 2-0 will be happy with a draw.
Not great but not terrible. The Gunners looked solid defensively for much of the match, limiting Schalke's chances. The forwards made chances of their own too, and Walcott should have won it at the end. The performance was by no means special, but to come to Schalke and walk away with a point is a good achievement for Arsene Wenger's men.
Sports Mole's man of the match
Jefferson Farfan: Farfan was a constant threat going forward for Schalke, linking up well with Huntelaar, Afellay and Holtby. The Peruvian also got his name on the scoresheet with the equaliser.
Walcott's miss. Theo Walcott had a golden chance to steal the three points with the last kick of the game as he raced clean through on goal. He seemed to be over-reliant on his right foot, however, and couldn't get the power or accuracy to beat the keeper.
Nicola Rizzoli had a decent game. He had a few penalty appeals directed his way, the first of which could have gone either way when the ball hit Mertesacker's hand in the box. Other than that his decisions were spot on.
Schalke: Next up for Schalke is a home match against Werder Bremen as they look to close the gap on Bayern Munich at the top of the Bundesliga.
Arsenal: Arsenal will be looking to get back to winning ways in the Premier League as they host Fulham before facing Spurs in the North London derby a week later.