Chelsea secured their first victory in Guus Hiddink’s second spell as boss to move six points clear of relegation with a deserved win at Crystal Palace.
Oscar put the Blues ahead against the run of play, tapping home after being put through by Diego Costa.
Once they scored Chelsea dominated, deservedly doubling their advantage with a spectacular Willian strike.
Costa sealed the win with a tap-in for a goal his performance deserved after Palace failed to clear Willian’s shot.
Interim boss Hiddink, who guided Chelsea to third in the Premier League, a Champions League semi-final and the FA Cup in his first spell at the club, remains unbeaten since taking over from Jose Mourinho last month.
The Blues’ four-match run without defeat is their longest this season and moves last year’s champions to 14th in the league, still 12 points adrift of a Champions League spot.
Chelsea’s away form in the first half of the season has been dire, with just six points collected on their travels. Only bottom two clubs Aston Villa and Sunderland have fared worse.
In beating seventh-placed Palace for their first away win since August, the Blues made a convincing case that the second half of the season might be more fruitful.
Hiddink said he needed leaders to pull the club out of relegation trouble and in Costa the Dutchman had a player in that mould, driving his team forward at Selhurst Park and playing a part in all three goals.
Like the rest of the Blues squad during this season’s dreadful title defence, the Spaniard – who had missed the goalless draw at Manchester United because of suspension – has been below par, but he gave one of his best displays of the campaign.
John Mikel Obi also shone, providing much-needed ballast to the Chelsea midfield.
The one disappointment for Hiddink was the injury to Eden Hazard, which ended the Belgian’s match after just 15 minutes.
Before the match Hiddink had said last year’s player of the season was “back in shape” after suffering a hip injury against Leicester and sustaining a knock in Monday’s draw at Manchester United.
Ultimately, Chelsea did not need Hazard against Palace with the impressive forward trio of Costa, Willian and Oscar creating plenty in his absence.
It was Palace’s first defeat in seven matches and they clearly missed key players, although Eagles boss Alan Pardew admitted that even with the likes of suspended Yohan Cabaye in the team his men would have struggled against Chelsea in such form.
The hosts, though, are a far less formidable side without the creativity of top scorer Cabaye in midfield, the pace of Yannick Bolasie on the flanks and Connor Wickham up front.
Palace are now without a win or a goal in their past three games, with Bolasie and Wickham not having played since the goalless Boxing Day draw against Bournemouth.
However, Pardew’s side had their chances with Wilfried Zaha – making his 200th appearance for the club – shooting wide with the score goalless and scuffing another opportunity just before Willian scored.