Arsenal defeated London rivals Chelsea 1-0 for their first win in four Premier League games on Sunday as a headed goal by stand-in striker Mikel Merino boosted their faint hopes of catching up with runaway leaders Liverpool.
Merino scored in the 20th minute when he stooped to flick his looping header over Robert Sanchez in the Chelsea goal after a Martin Odegaard corner.
The Spanish midfielder, who has led Arsenal's attack in the absence of injured colleagues in recent weeks, came close to a second goal in the 60th minute but his side-footed volley was kept out by a fine save by Sanchez.
Chelsea were also missing firepower up front with top scorer Cole Palmer absent through injury while centre forward Nicolas Jackson remains sidelined, also due to injury.
Without them, Chelsea struggled to threaten Arsenal's backline. The closest they came to an equaliser was in the 37th minute when defender Marc Cucurella hammered an angled volley at David Raya only for the ball to squeeze through the Arsenal goalkeeper's hands and go just wide.
The win left second-placed Arsenal 12 points behind Liverpool who face Newcastle United in the League Cup final later on Sunday.
Both the top two teams have played 29 games with a further nine rounds of fixtures to go.
Chelsea are fourth, one point ahead of Manchester City and five behind third-placed Nottingham Forest.

F1 confirms Abu Dhabi Grand Prix will close 2026 season
Norris wins Dutch GP as Antonelli stretches his F1 lead
Salah scores twice as Trabzonspor beat Basaksehir
Late Gvardiol strike earns Maresca winning start, Liverpool snatch last-gasp draw
Dutch GP re-starts after Verstappen crashes on opening lap
