Chelsea eased into the Capital One Cup quarter-finals after goals in each half from Spanish duo Cesar Azpilicueta and Juan Mata earned Jose Mourinho's side a 2-0 victory over Arsenal at the Emirates Stadium.
The Blues defender put the visitors ahead as they countered from a Gunners corner, capitalising on a poor header backwards by fellow right-back Carl Jenkinson.
It marked Azpilicueta's first goal as a Chelsea player, after diverting the ball past the outrushing Lukas Fabianski, and in off the post.
Arsene Wenger's side were on top for much of the evening, but after failing to break down a resilient away side and restore parity, Chelsea doubled their lead after the hour mark, when a brilliant individual strike from Mata booked his side's place in the fifth round.
Intercepting a clearance on the edge of the Arsenal box, the 25-year-old unleashed a swerving shot beyond the helpless home goalkeeper, and proceeded to celebrate in emphatic style in front of the Chelsea supporters.
Arsenal: Fabianski; Jenkinson, Koscielny, Vermaelen, Monreal; Ramsey (Park 81), Wilshere; Rosicky, Cazorla, Miyaichi (Ozil 63); Bendtner (Giroud 67).
Chelsea: Schwarzer; Azpilicueta, Cahill, Luiz, Bertrand; Mikel, Essien; De Bruyne (Ramires 69), Mata (Kalas 93), Willian; Eto'o (Ba 81).