Chelsea missed the chance to close the gap on Tottenham in the race for a top-four finish on Saturday, drawing 0-0 in the Premier League's early kick-off at Stamford Bridge.
The draw left fifth-placed Chelsea five points adrift of a coveted Champions League qualifying berth, and fourth-placed Tottenham were unlucky not to take all three points after twice going close late on.
Spurs, bidding to secure their first league win at Chelsea since 1990, enjoyed the better of the chances without ever managing to dominate their London rivals in a game played in brilliant sunshine.
Tottenham manager Harry Redknapp praised his side's performance but warned they still faced a fight to finish in the top four.
"I thought we were excellent. We kept the ball well, defended well and had some great chances," Redknapp told Sky Sports television.
"Since I've been here that's the closest we've come to winning here. I thought we edged it. I felt every time we broke out we looked dangerous."
Redknapp insisted his team's belief had never wavered despite a poor run which had seend them take just one point from a possible 12 in the four games leading up to Saturday's derby.
"We haven't been bad if you look at the games. I would be the first to say so. The confidence has never gone," Redknapp said.
"It was a big point for us. It keeps them five points behind us.
"It was a tough away game. We have a decent enough run-in but you have to be at it in every game."
But Chelsea interim manager Roberto Di Matteo admitted his team now faced an uphill struggle to secure Champions League qualification.
"I think it is a fair result. Both teams had chances to win the game. We tried hard in the second half to win it and put strikers on," Di Matteo said.
"They defended deep. We just didn't create enough clear chances.
"We knew we were behind and had to catch up. It is not going to be easy but we will try to the end."
The best chance of a lacklustre first half came two minutes into injury time, when Tottenham attacker Rafael van der Vaart spurned a golden opportunity, denied by a Petr Cech save and a goal-line block by Ashley Cole.
Chelsea's only genuine chance on goal came on 73 minutes when a Juan Mata free-kick hit the woodwork with Tottenham goalkeeper Brad Friedel well-beaten.
Blues substitute David Luiz was unable to get into position to rifle in the rebound and the chance had gone.
At the other end, Chelsea had transfer window signing Gary Cahill to thank for a superb sliding block from Emmanuel Adebayor on 79 minutes, the England international cutting out the Togolese striker's effort after he had successfully rounded Petr Cech and shot.
From the ensuing corner Tottenham midfielder Gareth Bale crashed a thumping header off the crossbar but Chelsea escaped again.
In the final minute of injury time Cech was on hand once more to parry away a vicious long-range free-kick from Bale as Chelsea hung on for the point.