Timber Boost for Arsenal Ahead of Chelsea Clash, But Guimaraes and Mosquera Doubtful

Arsenal could hand Jurrien Timber his first appearance of the season against Chelsea on Sunday, with Mikel Arteta confirming the Dutch defender is "in really good condition" after returning to full training following groin surgery that also ruled him out of the World Cup.

Arteta faces a more uncertain picture elsewhere in his squad, with Bruno Guimaraes and Cristhian Mosquera both being assessed after picking up knocks during last week's 1-0 win at Aston Villa. Guimaraes, who made his competitive debut off the bench at Villa Park, missed Thursday's open training session, while Mosquera was withdrawn during the second half as a precaution. "It was more precaution than anything else, so we will have to see how he feels," Arteta said of Mosquera, with £51m signing Ezri Konsa in line to deputise if needed. William Saliba remains a longer-term absentee.

Chelsea arrive at the Emirates unbeaten with three wins from three under Xabi Alonso and in free-scoring form, though they carry their own fitness concern over Moises Caicedo, who was forced off again with the same injury issue during last weekend's 4-3 win over Brighton after returning from a previous spell out.

The London derby represents the toughest test yet of Arsenal's title defence, with both sides having made big-money additions to their squads over the summer ahead of Sunday's Emirates showdown.