Mesut Özil shrugged off the after effects of a stomach virus to inspire Arsenal to a tricky 3-1 victory at Sunderland whose manager, Paolo Di Canio, was sent off. Özil, newly arrived from Real Madrid for £42.5m, picked up the bug but recovered in time to set up Olivier Giroud for Arsenal's first goal before creating several more first-half chances, most notably for Theo Walcott. The victory took Arsenal to the top of the table on goals scored ahead of Tottenham, 2-0 winners at home to Norwich, and Liverpool who visit Swansea on Monday night.

"Mesut had been sick," Arsène Wenger said. "He didn't feel well and I only decided to play him this morning, but he was outstanding in the first half. Mesut was like the team, outstanding in the first half, dropped in the second half."

The Arsenal manager, who is likely to be without Santi Cazorla until after next month's international break, conceded his side were a little taken aback by Sunderland's second-half revival. After Craig Gardner equalised from a penalty Aaron Ramsey scored twice, but between those efforts Jozy Altidore had a goal disallowed after the referee, Martin Atkinson, declined to play advantage following Bacary Sagna's foul on the striker, pulling play back and awarding Sunderland a free-kick. Later, during a break in play, Di Canio quizzed the official on the incident and the home manager was ordered to the stands.

"We were a bit lucky from it," Wenger said. "Sunderland were a different proposition in the second half. They came back strongly. Sunderland are interesting. It was an interesting game. Theo had opportunities but he couldn't finish."

"Altidore's disallowed goal was controversial. It was one of those things. If [the referee had played advantage and] there was no goal people would have complained because there was no free-kick."

While Wenger expressed concern about the knee injury which forced Giroud's late withdrawal – "we hope it's not serious," he said – Di Canio was left to reflect on what might have been after a defeat that leaves his radically rebuilt side with a solitary point from four games. "It wasn't easy," he said. "We have so many new players communication is tough at the moment. Four games, one point is not very good but there were plenty of positives. It was important we came back in the second half and got on top. We have started to play some good football."

He rued the referee's Altidore ruling. "That could have decided the outcome of the game. It was clearly a wrong decision but that can happen to anyone." Atkinson did not react well when Di Canio told him so. "He said: 'If you keep going I'll send you to the stand'," he said. "So I say: 'If you want to complete the perfect day you have to send me off.' So he said: 'Off you go.' He would probably say I invited him to send me off."