London - Arsenal manager Arsene Wenger said Diego Costa had got Per Mertesacker sent off after his side's Premier League title hopes were dented by Sunday's 1-0 home defeat by Chelsea.
Mertesacker was shown a straight red card for a last-man foul on Diego Costa in the 18th minute and Costa scored the game's only goal five minutes later, dispatching a cross from Branislav Ivanovic at the near post.
Costa had been the catalyst behind Gabriel's dismissal in September's reverse fixture, goading the Brazilian defender into kicking out at him as Chelsea won 2-0, but while Mertesacker's foul on him seemed clear-cut, Wenger felt that the blame once again lay with the Spain striker.
"He has got two players sent off this season," Wenger said. "I am accusing him of nothing, but those are the facts."
Backtracking somewhat, the Frenchman added: "That is part of a striker's game of course, and Costa is very good at that."
Chelsea interim manager Guus Hiddink said that referee Mark Clattenburg had been correct to dismiss the German defender.
"No, there was no doubt," he said. "Diego could run straight to (goalkeeper) Petr Cech, but was tripped. It's obvious that it was a red card without any discussion."
The result prevented Arsenal from reclaiming top spot in the Premier League from Leicester City and left them in third place, below Manchester City on goal difference.
Chelsea captain John Terry said that his side's controlled performance would give the champions belief in their quest to close the 14-point gap that separates them from the Champions League places.
"Mentally we were sound and on top," Terry told Sky Sports.
"As soon as they had the man sent off they sat back, so we pressed up higher and won the ball back. We are delighted with the win.
"Anything is doable. Everybody is beating everybody else. It is a tough league and if we put a run together we have a good chance (of finishing in the top four).
"We will fight until there are no points to play for."