Chelsea offered a chink of light to Manchester City in the Premier League title race after a stormy 1-1 home draw with Burnley on Saturday that gave more ammunition to their outspoken manager Jose Mourinho.
Branislav Ivanovic's knack of scoring crucial goals had seemingly set the hosts on their way to another routine victory, but Chelsea's Nemanja Matic was sent off and Ben Mee headed an equaliser for Burnley in the 81st minute.
Chelsea also had two strong penalty claims rejected and their lead at the top can be cut to five points if City beat Newcastle United in Saturday's late game.
Manchester United's top-four hopes were dented in a 2-1 defeat at Swansea City, who completed the double over Louis van Gaal's side having claimed three points at Old Trafford in the first game of the season.
Bafetimbi Gomis deflected in Jonjo Shelvey's long-range strike for Swansea to send United down to fourth in the table, 13 points off the top and one below Arsenal, who beat Crystal Palace 2-1 at Selhurst Park.
Tim Sherwood's first match as Aston Villa manager ended in disappointment as his new charges squandered a first-half lead to lose 2-1 at home to Stoke City, who scored a stoppage-time penalty from Victor Moses to snatch the points.
At the bottom of the table, Hull City moved four points clear of the relegation zone with a 2-1 win over fellow strugglers Queens Park Rangers. Sunderland and West Bromwich Albion drew 0-0.