With the pressure off, Arsenal and Manchester City each breezed to one-sided 4-0 victories on Saturday as they kept their Premier League titles hopes flickering.

Nigerian teenager Alex Iwobi scored for the second game running as Arsenal crushed their FA Cup conquerors Watford, while Kevin De Bruyne netted on his return from injury as City eased to victory at Bournemouth.

West Ham United dropped points in the race for Champions League qualification after Cheikhou Kouyate was sent off in a 2-2 home draw against London rivals Crystal Palace.

Meanwhile, Newcastle United were left six points adrift of safety after Martin Olsson's dramatic 93rd-minute goal earned Norwich City a potentially pivotal 3-2 win in a relegation tussle at Carrow Road.

Watford's 2-1 win at the Emirates Stadium last month ended Arsenal's two-year reign as FA Cup holders and Arsene Wenger's side claimed a measure of revenge as the teams resumed hostilities in north London.

Alexis Sanchez broke the deadlock in the fourth minute, scoring at the second attempt after Heurelho Gomes had parried his header from Iwobi's cross.

Sanchez returned the favour to Iwobi by teeing up the 19-year-old for a cool finish seven minutes before half-time and second-half goals from Hector Bellerin and Theo Walcott completed victory.

City had a similarly straightforward afternoon at Dean Court as Manuel Pellegrini's men tuned up for their mid-week trip to Paris Saint-Germain in the Champions League quarter-finals by steamrollering Bournemouth.

Fernando opened the scoring in the seventh minute with a neat finish from a Jesus Navas corner before De Bruyne -- back in the team after two months out with a knee problem -- volleyed home sweetly from David Silva's flick.

Sergio Aguero added a third goal in the 19th minute with a header from Navas's cross before Aleksandar Kolarov slammed home a fine fourth in stoppage time.

Bottom club Aston Villa are 15 points from safety after their wretched season continued with an abject 4-0 home defeat by Chelsea, for whom Pedro Rodriguez scored twice.

Ruben Loftus-Cheek opened the scoring with his first league goal and Alexandre Pato crowned his long-awaited debut following his January loan move from Corinthians with a penalty in first-half stoppage time.

Results
Arsenal 4 (Sanchez 4, Iwobi 38, Bellerin 48, Walcott 90) Watford 0
Aston Villa 0 Chelsea 4 (Loftus-Cheek 26, Pato 45+3-pen, Pedro 46, 59)
Bournemouth 0 Manchester City 4 (Fernando 7, De Bruyne 12, Aguero 19, Kolarov 90+3)
Norwich 3 (Klose 45+2, Mbokani 74, Olsson 90+3) Newcastle 2 (Mitrovic 71, 86-pen)
Stoke 2 (Afellay 13, Bojan 53) Swansea 2 (Sigurdsson 68, Paloschi 76)
Sunderland 0 West Brom 0
West Ham 2 (Lanzini 18, Payet 41) Crystal Palace 2 (Delaney 15, Gayle 75)