Tore Andre Flo returned to haunt Tottenham and revive their nightmare spectre of relegation with the decisive Chelsea breakthrough 15 minutes from the end of a vibrant London Premiership derby at Stamford Bridge.

And just for good measure the lanky Norwegian striker who grabbed a hat-trick when Chelsea thrashed their London neighbours 6-1 at White Hart Lane in December helped lay on a second for player-manager Luca Vialli with just three minutes left.

That final goal enabled the Italian to stay one goal ahead on 18 as Chelsea's top scorer in front of Flo who was making only his 19th start of the season.

And although Chelsea again showed major changes in their starting line-up following the midweek defeat at Leeds, Vialli and Flo now look an automatic pairing for Thursday's European Cup Winners Cup semi-final second leg against Vicenza when the Londoners need to overhaul a single-goal deficit.

Their win over Spurs added much-needed consistency to their league record which had previously show five defeats in seven under Vialli's command.

But it was a black day for Spurs who have not beaten Chelsea in eight years, and at the end of an unbeaten three-match run, are now hovering even more uncomfortably over the bottom three in the table.

In between the two late Chelsea goals Spurs substitute Les Ferdinand - coming on just before the hour for his first game since February - had a wonderful chance to rescue a point.

Sol Campbell's meaty cross from the right found him unmarked just beyond the far post but the England striker's header flew agonisingly just wide.

Spurs had earlier appealed furiously for a penalty when Chelsea's Michael Duberry appeared to bring down Jurgen Klinsmann 12 yards out as they challenged for a Rule Fox cross.

But England's World Cup referee Paul Durkin turned his back on their protests as he did a few minutes later at the other end when Vialli went flying over the challenge of Danish International Allan Nielsen who furiously berated the Italian for taking a dive.

There was no doubt about the Chelsea breakthrough when it came however in the 75th minute and, given the nervous nature of a lumbering Spurs defence, the biggest surprise was that it took so long to arrive.

Flo, who had lead England centre back Campbell a torrid dance all afternoon escaped him yet against to pop on the end of a delightful back heel by Vialli from teenager Jody Morris's through ball.

The Norwegian strode on to clip his shot calmly beyond goal keeper Ian Walker.

Chelsea survived Ferdinand's opportunity to rescue Spurs and rubbed in the taunts of the home crowd over that pre-Christmas thrashing when Flo and Dan Petrescu linked smartly for Vialli to shoot low past the helpless Walker for the clincher.

If Chelsea had taken their chances in the first half it would have been over as a contest much earlier.

Campbell twice allowed long balls to drift in behind him and in the 20th minute Flo's fierce drive demanded a thrilling full stretch save from Walker.

Another defensive error, this time by Steve Carr gave Vialli the glimpse of glory on the corner of the penalty box but his audacious chip shot just failed to defeat Walker's acrobatic stretch.

The temper was raised to boiling point in the second half and for a while Spurs threatened to get on top especially when Moussa Saib pounced on Vialli's careless pass deep in Chelsea territory but was muscled out of it from the edge of the box by Steve Clarke's alert challenge.

Ferdinand's appearance in place of Chris Armstrong showed Spurs ambition but almost immediately Chelsea brought on tough Uruguayan midfielder Gustavo Poyet for his first game since snapping a knee ligament in October and his midfield contribution was significant.

Tottenham's Ramon Vega stumbled over Poyet's challenge to give the ball to Vialli who set up Petrescu to shoot into the side netting when a goal looked certain.

And it was Poyet's pass which lead to Flo brushing off Campbell again before his shot was deflected inches wide.

Chelsea were well served by midfield teenagers Morris and John Harley, the latter making an impressive home debut on the wing before giving way to Poyet.

Teams

Chelsea: Ed De Goey, Petrescu, Leboeuf, Clarke, Vialli, Wise, Duberry, Le Saux, Flo, Morris (Myers 84), Harley (Poyet 59).

Subs Not Used: Hughes, Hitchcock, Zola.

Goals: Flo 75, Vialli 88.

Tottenham: Walker, Fox, Nielsen, Armstrong (Ferdinand 57), Carr, Ginola, Vega, Campbell, Klinsmann (Calderwood 67), Saib, Berti (Anderton 82).

Subs Not Used: Baardsen, Scales.

Booked: Berti.

Att: 34,149

Ref: P A Durkin (Portland).