(CNN) -- Tottenham blew the English Premier League title race wide open again with a 2-1 victory over 10-man leaders Chelsea that gave Manchester United hope after the champions' vital derby win earlier on Saturday.
Chelsea had gone into the match seeing their four-point lead reduced to one by second-placed United, who snatched a last-gasp 1-0 triumph at Manchester City to leave the season on a knife edge with three games to play.
Tottenham then followed up the midweek 2-1 victory against third-placed Arsenal to claim more London bragging rights, as Chelsea had captain John Terry sent off in the second half and could not score until the second minute of time added on.
Spurs, who travel to United next Saturday, moved two points ahead of City into fourth place as the hunt for the final Champions League place also took another twist.
Chelsea coach Carlo Ancelotti believes his side, who next face Wigan, Liverpool and Stoke, can still end United's run of three successive titles.
"We must not have a panic now. We have two at home and one difficult game away. We can be the best again -- a one-point lead is not bad at this stage of the season," the Italian told reporters.
"I am always confident. I am less confident than yesterday, but we are still in the best position."
Chelsea went behind in the 15th minute as England striker Jermain Defoe blasted home a penalty after referee Phil Dowd ruled that Terry had handled a cross.
The decision looked marginal, but was perhaps late justice for the former England captain, who escaped a blatant handball in the area in Tuesday's win over Bolton.
It could have been Tottenham's second spot-kick, as man of the match Gareth Bale had been brought down in the box minutes earlier.
Chelsea had the ball in the net eight minutes before halftime, but Florent Malouda was clearly offside, and then Bale made it 2-0 soon after as he cut inside Paulo Ferreira and whipped a low right-foot shot past goalkeeper Petr Cech.
The Welshman was also involved as Terry received his marching orders in the 67th minute, receiving his second booking after a late challenge on the pacy 20-year-old.
Bale, who also scored Tottenham's second against Arsenal, could have put his team further ahead as Chelsea fell apart at the back with all their substitutes already on the pitch when Terry departed, and he set up Roman Pavlyuchenko with a gift of a chance that the Russia striker volleyed wide.
England midfielder Frank Lampard gave Chelsea hope when he toe-poked in a low cross in the second of five extra minutes at the end, but Pavlyuchenko should then have made it safe for Spurs when he inexplicably missed in a three-on-one situation.
Manchester United had veteran Paul Scholes to thank for a vital victory in the derby at City, as the midfielder headed a last-gasp injury-time winner with just seconds left on the clock.
The 35-year-old, who signed a new 12-month deal on Friday, nodded in from Patrice Evra's cross as United scored a final-minute winner against City for the third time this season.
The former England international netted his 149th goal for the club to deliver a big blow to City's European hopes.
United had welcomed back top scorer Wayne Rooney after an ankle problem, but the England striker had a frustrating day and was replaced by Dimitar Berbatov with 15 minutes to play.
Everton kept alive their hopes of earning a Europa League place next season as substitute Aiyegbeni Yakubu inspired a 3-2 victory at mid-table Blackburn.
The Nigeria striker put the hosts 2-1 ahead with his first touch of the ball in the 79th minute, then set up Australia midfielder Tim Cahill to win it in the 90th after Jason Roberts had equalized for Rovers.
Spanish midfielder Mikel Arteta had put Everton ahead from the penalty spot in the fourth minute after being brought down by captain Ryan Nelsen, but was lucky not to be sent off after poking Blackburn midfielder Morten Gamst Pedersen in the eye.
French midfielder Steven Nzonzi leveled from long range in the 69th minute, but Yakubu's efforts left Everton in eighth place -- a point behind Aston Villa and two adrift of local rivals Liverpool, who face lowly West Ham on Monday. Villa travel to relegated Portsmouth on Sunday.
Birmingham stayed ninth after being held 0-0 at home by Hull, who stayed in the third relegation spot but are now just three points behind West Ham.
Europa League semifinalists Fulham claimed 10th place despite also being held goalless by Wolverhampton Wanderers, who stayed six points clear of Hull and now seem set for a second season in the top flight.
Stoke remained on 43 points, along with Fulham and Blackburn, after losing 2-1 at home to Bolton.
The hosts led in the 13th minute as Turkey international Tuncay Sanli set up striker partner Dave Kitson, but Matt Taylor grabbed two goals in the last five minutes to lift Bolton a point above Wolves and into 14th place.
Sunderland consolidated 13th place with a 2-1 victory at home to second-bottom Burnley thanks to first-half goals from strikes Frazier Campbell and Darren Bent, before Steven Thompson gave the visitors late hope.
Bent, who hopes to be part of England's World Cup squad, did his chances no harm with his 23rd league goal this season.