If finding a free evening to accommodate the replay was a problem, Jose Mourinho was not complaining last night as Chelsea, chasing an unprecedented Grand Slam, emerged from this enthralling FA Cup quarter-final with Tottenham Hotspur emboldened by the fact that no mission appears to be impossible.

Having blown the chance to take a 4-1 lead seven minutes after the restart, Martin Jol's side must wait until the replay a week today to try and finish the job they looked destined to achieve after first-half goals from Dimitar Berbatov, Hossam Ghaly and Michael Essien, the latter into his own net.

Only next time, Mourinho's Chelsea, caught out by Jol's inspired selection of Aaron Lennon in a supporting role just behind Berbatov and Jermain Defoe, will surely be better prepared. Without John Terry and Claude Makelele, who missed the tie with flu, Essien spent a hectic afternoon, playing no fewer than four positions.

Last week, against Porto in the Champions League, Mourinho got his point across with a rant and a rage at half time. Yesterday, it took an angry exchange with referee Mike Riley and some gesticulating on the touchline to mastermind Chelsea's spirited second-half recovery.

It took some guts, with captain Frank Lampard adding to his 21st minute equaliser with a poacher's strike in the 70th minute and young substitute Salomon Kalou forcing the replay with an assured volley just four minutes before time.

"I think we deserve a second chance," said Mourinho, who has yet to get his hands on the venerable trophy.

However, Tottenham will be kicking themselves. So dominant in the first half, with Lennon in full flight and Berbatov giving Chelsea's patched-up defence kittens with every deft and devious touch, the visitors looked ready to end Mourinho's 79-match unbeaten record in domestic affairs at Stamford Bridge, and but for some seriously tired limbs, they would surely have done that.

If the loss of Berbatov 15 minutes from time with a pain in his groin was significant - replacement Mido was an embarrassingly inept understudy - so, too, was the fact that Tottenham had played Braga in Portugal on Thursday, two days after Chelsea's home game against Porto.

Seventeen years have elapsed since Gary Lineker came to the Bridge with Tottenham and ousted Chelsea in an FA Cup competition that they eventually went on to win.

Yesterday, even without Paul Robinson in goal and the in-form Robbie Keane, there was cause for optimism as Jol's attack-minded outfit. In their last five games, four of which were away from home, they've scored 17 goals and set about their opponents with pace and no little cunning here.

Petr Cech, the Chelsea goalkeeper, boasted seven clean sheets in 10 games but that did not deter Berbatov, who used both finesse and power to take possession of Lennon's delightful flick and then fire beyond the Chelsea goalkeeper in the fourth minute.

Quick-witted, sharp and strong, the Bulgarian was at his eye-catching best, a willing target for both his defence and midfield. For once, Didier Drogba was cast in the shade, his 29th birthday celebrations overshadowed by a striker in the form of his career.

Yet Drogba, impatiently awaiting his 30th goal of the season, can claim a hand in Chelsea's equaliser. It was his cross on the right edge of the Tottenham penalty area that picked out Andriy Shevchenko whose wayward strike was turned in by Lampard in the 21st minute.

If Mourinho believed that the danger had passed, he was mistaken. Within seven minutes, Essien, deputising for Terry at centre-half, turned Lennon's clever delivery into his own net. Clearly rattled by Berbatov's presence, Essien swung a wild leg when Cech was perfectly positioned to deal with the cross.

At the opposite end, Paul Staltieri cleared off the line before Mourinho made the first of several tactical changes. Off came right-back Paulo Ferreira and on came Shaun Wright-Phillips, initially as a wing- back. Within five minutes, the excellent Ghaly had extended Tottenham's lead, starting and finishing the move with aplomb.

It was then left to Lennon to provide the coup de grace, when one-on-one with Cech moments later. Instead, the shot was blocked and Chelsea never looked back.

Within four minutes of Mido replacing Berbatov, Lampard had nailed a loose ball from a Chelsea set-piece and as Spurs' energy levels dipped dramatically, Kalou rattled in the equaliser, following Ricardo Carvalho's pump upfield and Drogba's brave header.

In the dying moments, Defoe struck the bar but by then Tottenham were resigned to a replay, at White Hart Lane, where they beat Chelsea in the league this season.