Jimmy Floyd Hasselbaink fired Chelsea to within four points of leaders Arsenal and extended Tottenham's winless run against their rivals to 28 games.
The Dutchman fired the only goal of the game on 38 minutes to cap a great week for boss Claudio Ranieri.
The Italian was named Manager of the Month for March and had the pressure on his job eased with the announcement that England coach Sven-Goran Eriksson had signed a new contract.
It was a cool performance by Chelsea, coming just three days before their massive Champions League tie at Arsenal.
Ranieri surprised many at the stadium by naming a strong line-up which included the likes of Irish international Damien Duff and French star Claude Makelele.
Tottenham, who had boasted an unbeaten record at home in the league this year, had been boosted by captain Jamie Redknapp's first start since September having had an injury-ravaged campaign.
It appeared to galvanise the home side who showed no sign of an inferiority complex against a team they had failed to beat in the league for 14 years.
With just three minutes on the clock, Tottenham striker Jermaine Defoe, who made his debut for England in the 1-0 defeat against Sweden on Wednesday night, whisked in a dangerous cross which Italian keeper Marco Ambrosio did well to gather.
But Chelsea quickly got into their stride and Frank Lampard went close to breaking the deadlock when he skipped past a couple of challenges only to see his fierce shot go over the bar.
On 19 minutes, Chelsea were unfortunate not to be in front when Duff's corner was met by the head of Hasselbaink, but striker Robbie Keane cleared his effort off the line.
Tottenham came back strongly however and Defoe made some space on the edge of the area before firing in a low shot, but Ambrosio saved smartly.
The home fans then had their heads in their hands when Keane put a delightful ball through to fellow Irish international Stephen Carr, but he failed to control it.
Then defender Ledley King headed horribly wide after Christian Ziege had found him in acres of space with a delightful cross into the area.
Tottenham were made to pay seven minutes before the break with Hasselbaink's goal which capped a brilliant move by the visitors.
Duff was found in acres of space on the left and he squared a great ball into the box for the Dutchman to fire his fourth goal in two games.
But Tottenham still could have gone into the break level as Keane charged into the penalty area on the left hand side and fired a low shot toward the near post, but Ambrosio saved with his feet.
Tottenham caretaker-boss David Pleat brought on a third striker in Freddie Kanoute to link up with Keane and Defoe in the second half in an attempt to change the game.
But Pleat's side were left cursing their fortune as two penalty appeals fell on the deaf ears of referee Steve Bennett.
Michael Brown's fierce shot from the edge of the area appeared to be heading into the corner before John Terry appeared to use his arm to deflect it wide.
And Keane looked set to score minutes later but fell under a Terry challenge only for Bennett to ignore his appeals.
The ball still fell to Kanoute but from close range he could find no way past Ambrosio, who impressed once again in the Chelsea goal.
Chelsea always posed a threat on the counter-attack and could have extended their lead on a number of occasions.
Frank Lampard and Eidur Gudjohnsen were both denied at close range by superb stops from Kasey Keller.
Ranieri's side were able to see the last few minutes out with ease and secure qualification for next season's Champions League in the process.
Ranieri believes Chelsea still have a great chance of catching the Gunners in the race for the title.
He said: "We are not looking at where Arsenal are because we are only concentrating on ourselves.
"There are seven games left and we want to do our best. We are in good condition and playing good football.
"The three points were very important for us today. We are now very close to doing something very important for Chelsea.
"We want to improve on last season and everything is now in our hands, but we must continue to play with this mentality." But Ranieri conceded his side had been given a real fright by Spurs and was thankful to secure the club's fifth successive Premiership win for the first time in the club's history.
He added: "In the first half Tottenham put us under a lot of pressure and they put a lot of dangerous crosses in.
"Tottenham are a good team and play good football. Our keeper Ambrosio put in a great performance." But Pleat was furious at his side's failure to break Chelsea's hoodoo and Bennett's refusal to give them a penalty for Terry's handball offence.
He said: "We definitely deserved to get something. They only put one good cross in the first half and it led to their goal, but Duff looked offside.
"We should have had a penalty - there is no question about that. You could tell by the reaction of all the players that they knew it was a penalty.
"Bennett missed it, it was as simple as that although I thought he had a good game apart from that.
"But there were others that could have been given. Keane was pulled down twice in the area, but it was in the situation where the referee favours the defender.
"We needed to come in at half time at 1-1 and we had the chances to do so in the first half. Chelsea sat off us and were defending under frantic pressure, but looked to counter. It worked for them and we always seem to lose to them 1-0." MAN OF THE MATCH: Damien Duff – The Irishman's return to the team has coincided with Chelsea's improved recent run and he was outstanding again against Spurs.