Wenger warning after Arsenal throw away two-goal lead
Manager Arsene Wenger was left to rue his side's missed chances after Arsenal threw away a two-goal lead to allow Schalke 04 to fight back and draw 2-2, leaving group B wide open.
The draw leaves Schalke top of the table with eight points while Arsenal are just a point behind in second.
Olympiakos are third on six points after their 3-1 win over bottom-placed Montpellier, leaving all still to play for in the group.
"It's an open group. I believe we are in a good position where you want to win your home game," said Wenger with Arsenal hosting Montpellier, bottom of group B, in a fortnight while Olympiakos are at Schalke the same night.
"Schalke have to win their game against Olympiakos as well, so it will probably come down to the last game."
England forward Theo Walcott squandered two clear chances to win the game, hitting the post in the final 15 minutes, then firing straight at Schalke goalkeeper Lars Unnerstall with virtually the last kick of the game.
"It's regrettable that we conceded a goal before the break, then missed a goal with the last chance of the game. They both had a great influence on the result," admitted Wenger. Walcott proved his recent injury is behind him on 18 minutes with the opening goal before France's Olivier Giroud added the second on 26 minutes with a header from a Lukas Podolski cross.
Schalke hit back as Holland's Klaas-Jan Huntelaar scored on the stroke of half-time, before Peru's Jefferson Farfan equalised on 67 minutes to claim a point.
But Wenger praised his England star Walcott, who looked dangerous throughout on his return to the side.
"Theo did well. He had a positive attitude. He was the one you always felt who could have decided the game and it wasn't an accident that he had a chance to win the game in the last minute," said Wenger. "I felt overall we played reasonably well, but we dropped off in the second-half.
"I felt we showed a good response to Saturday's game [a 2-1 Premier League defeat at Manchester United] and the team is getting better."
Schalke had their chances to win the game with 20 shots on goal, compared to Arsenal's eight, and the lion's share of possession.
"In the end, we can be happy with the draw," said Schalke midfielder Lewis Holtby.
"Coming back from a two-goal deficit is a reasonable achievement. It speaks for the morale of our team."