Everton defender Joleon Lescott scored an injury-time own goal to hand Chelsea the advantage after the first leg of their Carling Cup semi-final.
Lescott headed the ball into his own net as Shaun Wright-Phillips closed in.
The Chelsea winger had opened the scoring with a curling strike before Jon Mikel Obi was dismissed following a sliding tackle on Phil Neville.
Yakubu then equalised with a brilliant shot on the turn while James McFadden hit the post for Everton.
And even after Lescott, under pressure from the impressive Wright-Phillips, had put the ball into his own net Everton might have grabbed a second equaliser.
Lescott found himself through on goal and with a chance to almost immediately atone for his error but a heavy touch at a crucial moment saw the ball run away from him and Hilario was able to gather.
It was a far cry from the opening half, which Chelsea went on to dominate after Wright-Phillips struck with 25 minutes played.
Lee Carsley allowed Wright-Phillips to drift into the Everton area and the Chelsea winger turned sharply before finishing brilliantly after collecting a pass from Florent Malouda.
Everton all too often gave Chelsea too much time and space and Joe Cole almost scored after eluding Phil Jagielka before bursting through on goal.
Cole saw his shot smothered by Tim Howard but referee Peter Walton, having initially played an advantage, awarded Chelsea a free-kick for Jagielka's challenge and Michael Ballack missed by inches with a fizzing strike.
Everton looked relieved to reach the break without conceding again but Wright-Phillips was once more gifted far too much space a minute into the second half and forced another save from Howard.
Chelsea seemed intent on trying to establish a decisive first-leg advantage but their attacking ambitions were undermined when Mikel was dismissed for his tackle on Neville.
The Nigerian appeared intent on trying to win the ball but his studs were showing and Walton had no hesitation in dismissing the player.
Despite the sending-off Chelsea still managed to fashion a great opening but Claudio Pizarro, after collecting Wright-Phillips's superb through ball, failed to connect cleanly and within minutes Everton were level.
Yakubu, mostly absent for the first 64 minutes of the tie, brilliantly equalised after Joseph Yobo had hooked McFadden's free-kick back into the danger zone.
McFadden then hit the post from the tightest of angles after a mazy run down the left as Everton suddenly started to dominate.
But Lescott put the ball in his own net after he was caught stationary by Wright-Phillips at the far post.