Former Arsenal striker Jeremie Aliadiere denied his old club a Premier League victory at Middlesbrough on Saturday when he headed an equaliser in a 1-1 draw at a rain-sodden Riverside Stadium.
Arsenal, needing a victory to stay in touch with the title race, took the lead after 17 minutes when Emmanuel Adebayor was left unmarked to head in a Cesc Fabregas corner.
Their lead only lasted 12 minutes as Aliadiere reacted brilliantly to swoop and head Tuncay's driven cross past a helpless Manuel Almunia.
Arsenal had an escape before halftime when Boro winger Adam Johnson appeared to be brought down in the area by Gael Clichy but no penalty was awarded.
The Gunners dominated for much of the second half but were left frustrated as they dropped more points on the road. They remain in fourth spot with 30 points, seven behind leaders Liverpool who are at home to Hull City later on Saturday.
Champions Manchester United, in third place, are at Tottenham Hotspur in an early evening kickoff while second-placed Chelsea play West Ham United on Sunday.