Chelsea's Champions League fate will go to the final group game after an unconvincing 4-0 win over 10-man Maccabi Tel Aviv earned successive victories for the first time in two months.
Porto's home loss to Dynamo Kiev means progression from Group G is by no means certain for Chelsea, who beat Norwich last Saturday and host Jose Mourinho's former side in Europe on Dec. 9.
A draw should be enough for the Blues to advance to the knockout stages.
Gary Cahill scored from a corner and former Chelsea defender Tal Ben Haim was shown a straight red card before half-time for a wild kick at Diego Costa, who had an altercation with Mourinho at the interval.
Willian added a free-kick strike -- his sixth set-piece goal of the season -- Oscar headed in a third and Kurt Zouma a fourth at Haifa's Sammy Ofer Stadium to put a gloss on the scoreline.
There was plenty for Mourinho to ponder, though, after a bust up with Costa and with John Terry departing on a stretcher with a foot injury.
Mourinho and Costa had a frank exchange as the teams left the field for half-time and Loic Remy was sent out to warm-up.
But Costa completed the game as Chelsea struggled to assert themselves and lost their talismanic skipper to injury.
Mourinho was also less than impressed by a pitch which he took it upon himself to repair after Cahill's goal, replacing large divots near his technical area.
Just a third win in 11 Champions League away games -- and first in a year, since the 5-0 victory at Schalke -- earned the Blues successive wins for the first time in two months, when they beat Maccabi Tel Aviv, Arsenal and Walsall in consecutive games in September.
Tottenham await in the London derby on Sunday. Chelsea lost 5-3 at White Hart Lane on January 1 and a third straight win would be a real sign of a resurgence.
Maccabi Tel Aviv were the only team in the group stage yet to register a point and had scored one goal prior to the contest.
Chelsea won 4-0 at Stamford Bridge, but Mourinho guarded against complacency by reminding his men of last season at Maribor, when the Blues drew in Slovenia after a 6-0 drubbing in London.
Former Watford boss and ex-Chelsea midfielder Slavisa Jokanovic's side -- playing 60 miles from home in a venue more suitable to European football -- began well with Dor Peretz heading over and Nosa Igiebor slicing wide following yet more uncertain Chelsea defending.
The Blues' approach play was strong, but lacked the finishing touches and Cesar Azpilicueta shot wide before Baba Rahman centred, only for Chelsea's forwards to be absent.
Chelsea went in front when Cahill met Willian's corner, Predrag Rajkovic turned the ball on to the post and the defender met the rebound with a simple tap in.
Mourinho turned groundsman aware that his team had more repair work to do before Ben Haim was shown a straight red for a kick which appeared more mis-timed than malicious.
It was still far from easy for Chelsea as Asmir Begovic was required to spread himself to deny Eli Dasa and made a finger-tip save from Eran Zahavi after Azpilicueta had been denied by Rajkovic. Terry was in agony after a challenge in midfield and departed as Willian lined-up a free-kick which he subsequently curled in.
Rahman then crossed for Oscar to head in a third and Zouma added a fourth.