Arsenal forward Gabriel Jesus will need surgery on a serious knee injury as Gunners boss Mikel Arteta scrambles to replace the Brazilian in the January transfer window.

Jesus was stretchered off in the first half of Sunday's FA Cup third-round match against Manchester United, which ended in a defeat for the Gunners on penalties.

The 27-year-old saw specialists this week to assess the extent of the problem, which has now been diagnosed as an anterior cruciate ligament injury to his left knee.

Jesus could be sidelined for the rest of the season in a major blow to Arsenal's hopes of winning a first Premier League title since 2004.

"Gabby will undergo surgery in the coming days and will soon begin his recovery and rehabilitation programme," Arsenal said in a statement on Tuesday.

"We will continue to keep everyone updated with Gabby's recovery, with everyone at the club fully focused on supporting Gabby to ensure he is back to full fitness as soon as possible."

After scoring just once in his first 20 games in all competitions this season, Jesus had netted six times in six matches before the United match.

The former Manchester City star's injury, combined with the extended absence of England forward Bukayo Saka after hamstring surgery, has added to growing concerns over Arsenal's lack of goalscoring threat.

Arsenal are second in the Premier League table ahead of Tuesday's matches, six points behind leaders Liverpool, but they have failed to win any of their past three games in all competitions.

Arteta's men face an uphill battle to qualify for the League Cup final after a 2-0 home defeat by Newcastle and are out of the FA Cup.

Arsenal are the only club in the Premier League's top six without a goalscorer in double figures -- Kai Havertz has seven in the English top-flight this season.

Arteta, whose team face Tottenham in Wednesday's north London derby, was asked at his pre-match press conference whether the club were targeting a striker in the January transfer window.

"We are actively looking in the market to improve the squad, and that's been since day one," said the Spaniard, who had admitted he was "very worried" about Jesus's injury before receiving the gloomy medical update later in the afternoon.

"We would be naive not to do that because it's an opportunity always to evolve the team, to improve the squad, and especially with the circumstances that we have.

"So yes, we are looking and we are trying, and let's see what we are able to do."

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