Arsenal manager Arsene Wenger has claimed centre-back Gabriel Paulista will be out of action for three weeks after suffering an injury during the 2-1 victory over Queens Park Rangers – meaning he will miss the FA Cup clash against Manchester United.
The Gunners secured another victory to maintained their third position in the Premier League table thanks to goals from Olivier Giroud and Alexis Sanchez.
However, the Brazilian January signing was replaced by Lauren Koscielny during the first-half of the London derby after suffering a knock.
Wenger confirmed after the game the former Villarreal star sustained a hamstring injury and may be on the sidelines for some weeks.
"It's a hamstring. I don't know, it's bad enough to come off. It's usually 21 days, not years!," the boss confiremd.
Meanwhile, the manager praised Sanchez after the Chilean international regained his best form while scoring his first goal for seven games
"It's good because when you don't score for seven or eight games it is on your mind, even if you don't say so. He took his chance well, he's tricky, had a short back lift and scored a good goal," he said.
"He never gives up and that's the strength of a good striker as well. He's resilient and I don't know what happened before because it looked like, for someone who was desperate to score, he could have taken the chance and he waited for somebody. After that, the fact that he could still score shows that he has the mental strength to respond."
Wenger also hailed Olivier Giroud's responce to his error-strewn performance against Monaco in the Champions League, with the Frenchman having netted goals in the Premier League victories over Everton and QPR.
"We were all down after the Monaco game and we responded well against Everton and again today. The confidence we got against Everton paid off tonight," he said.
"He's strong mentally. He can take some criticism and respond. He's shown that. I feel it was a bit harsh for him because he missed some chances. That can happen. Where we were guilty was to concede the goal."