Arsene Wenger admitted Arsenal’s hopes of finishing in the top-four were increasingly slim after their 1-0 loss to Tottenham at Wembley on Saturday.
Harry Kane’s header early in the second half condemned Arsenal to a seventh away defeat, and an eighth loss overall of an increasingly frustrating season, to leave them seven points behind their London rivals in sixth place.
Fourth-placed Liverpool are now six points clear of the Gunners with a game in hand and the gap could be even larger when Arsenal host Manchester City in their league game on March 1.
“It was a game we couldn’t afford to lose,” Wenger said afterwards. “It makes it much more difficult now, but we have to fight until as long as we have a mathematical chance.
“There was more at stake than just the derby, I said that before the game, that’s why it’s so disappointing to lose the way we lost it.”
Should Arsenal eventually fail to make the top four, they could still make it into Europe’s premier competition if they can follow in the footsteps on Manchester United and win the Europa League.
Wenger has spoken before of his reluctance to forget the Premier League and focus on Europe, and reiterated his stance after the derby loss.
“It’s too early,” he said. “Football is not about switching off for three games and switch it on for one.
“Manchester United decided that once they were in the semi-final, we are far from the semi-final. I think we have to fight to have a chance to come back.
“For me it’s a very disappointing result. The priority has to be to be in the Champions League through the Premier League. I’m not a great fan of qualifying for the Europa League through the Champions League.
“If it’s an opportunity we have to try and take it as well, but the priority is still the Premier League.”
Arsenal’s Europa League campaign gets back underway next week when they travel to Sweden for the first leg of their round-of-32 tie against Ostersunds.