Arsenal midfielder Thomas Partey was forced off injured during first-half stoppage time of his side's Premier League match against Tottenham.
Partey returned from injury to make his first appearance for the Gunners in over a month when he was named in the starting XI for the north London derby on Sunday.
He walked over to the touchline during the build-up to Harry Kane's goal that put Spurs 2-0 up and was replaced by Dani Ceballos immediately after and just seconds before half-time.
Partey had been out of action since he was taken off during the break, in his side's 3-0 defeat at home to Aston Villa on November 8 and subsequently missed the Premier League matches against Leeds and Wolves as well as the European encounters against Molde and Rapid Vienna.
The Ghana international only returned to Arsenal training during the week and coach Mikel Arteta said after his side's Europa League win against Rapid Vienna that the summer signing could feature against their city rivals.
Ahead of the game on Sunday, Arteta was asked about the 27-year-old's inclusion in the first team.
He told Sky Sports: "We didn't expect him to be fit for the game but he has been training well and ready to play."
Arsenal fell behind just 13 minutes into the match at Tottenham Hotspur Stadium. Son Heung-min led Spurs' charge forward, combining with striker Kane before lashing past Bernd Leno from outside the box.
Son then turned provider as he passed to Kane who then fired in to double the home side's advantage.
Tottenham were second in the table and one point behind Chelsea, who jumped into pole position with a win against Leeds on Saturday.
Arsenal, meanwhile, sat 15th in the table with 13 points from 10 matches, having won just one of their last six games in the English top-flight.
"A win would change the mood completely, it is not just the game it is also the occasion. We are here to win," Arteta said of his side's need for a good result.
"The way we will approach it will serve us to change the situation we are in in the league. We have to be at our best, they are a threat, they are in a really consistent form but we can beat them."
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