Arsenal lost ground in the race to secure a top-four finish as the Gunners slumped to a surprise 3-2 defeat against Swansea City, while Mark Hughes' debut as QPR boss ended in a 1-0 loss at Newcastle United on Sunday.
Arsene Wenger's side needed a win at the Liberty Stadium to keep pace with fourth-placed Chelsea, but Danny Graham's second-half winner condemned the north Londoners to their second successive league defeat.
Fifth-placed Arsenal, beaten by Fulham in their last league outing, are now four points behind Chelsea and 10 behind Tottenham in third.
Wenger left Thierry Henry on the bench despite his match-winning cameo role against Leeds United at the start of his brief return on loan from New York Red Bulls. It did not look like Henry would be missed as Robin van Persie put Arsenal in front in the fifth minute.
After a magnificent 2011, this was van Persie's first goal of the new year and the Dutch forward took it in style, running onto Andrey Arshavin's pass before clipping a cool strike past Swansea goalkeeper Michel Vorm at his near post.
But Swansea have lost only once at home since winning promotion from the Championship and the Welsh club fought back superbly to register victory.
Newcastle floor QPR
Mark Hughes made a losing start as Queens Park Rangers manager when the relegation-threatened side were beaten 1-0 at Newcastle United in the Premier League on Sunday.
Leon Best stroked home a fine winner in the 37th minute to send Newcastle up to sixth place, level on points with Arsenal. Third from bottom QPR have now gone nine games without a victory.