Mikel Arteta admits he is "really worried" about Bukayo Saka's hamstring injury that forced him off in the first half against Crystal Palace.

Saka limped off in the 24th minute at Selhurst Park and while Arsenal went on to win 5-1, the victory was marred by the blow to the England winger, who left the stadium on crutches.

"He felt something in his hamstring, he couldn't continue," Arteta said after the game. "He will have to be assessed so really worried about that one."

Asked if there is any information on the severity of the injury, Arteta replied: "It's very difficult to do that now."

The injury is an even bigger blow given Arsenal lost Raheem Sterling to a training ground injury on Friday.

Sterling, who has played 11 games for the Gunners since arriving from Chelsea on loan, will undergo tests with Arsenal's medical team to determine the extent of the injury.

"We don't know how long that is as well," said Arteta. "To lose two players within 24 hours, it's not good.

"With the amount of games playing every three days, it doesn't surprise me. But the team will react to that."

It is not the first hamstring injury Saka has suffered this season. The winger limped off while on England duty during the October international break and was sidelined for a few weeks, missing Arsenal's 2-0 loss to Bournemouth.

Saka also picked up a leg injury in May which forced him to miss Arsenal's final game of last season against Everton.

"I'm not sure if it's exactly the same one," said Arteta about whether he has aggravated his hamstring injury from a few months ago. "It's in the same leg. He had the third minor injury - I don't know how big this is going to be. But he already had two."

Arsenal won 5-1 at Crystal Palace to move within three points of Premier League leaders Liverpool, who have two games in hand ahead of a trip to Tottenham on Super Sunday, live on Holaports.

Gabriel Martinelli, who took over Saka's duties on the right wing, got on the scoresheet while Gabriel Jesus, Kai Havertz and Declan Rice also found the net in south London.