Thierry Henry put Arsenal ahead before two goals in the last ten minutes from Ireland midfielder Rory Delap seemed set to condemn Arsenal to a second successive defeat after a 2-0 loss against Manchester United had ended their record run of 49 unbeaten league games.

But Dutch ace van Persie, who scored in the League Cup midweek, equalised in the last minute to save face for the Gunners as Chelsea cruised to a 4-1 win at West Bromwich to go level on points at the top of the Premiership.

Manchester United, however, were hit by a shock 2-0 defeat at Portsmouth.

"We had chances to score the second goal but they scored from two good set-pieces," said Arsenal manager Arsene Wenger.

"From then on we were on the back foot but we found the resources to come back to 2-2.

"It was a shock but when you play 49 unbeaten the most important thing for me was not to lose the next game and that's what we did," said Wenger after seeing Henry miss from the penalty spot in the 29th minute.

United could not build on their victory over Arsenal last weekend as Portsmouth beat them at Fratton Park for the second season in a row.

Harry Redknapp's side got through the first half unscathed and took a shock lead eight minutes after the interval through a David Unsworth penalty.

Rio Ferdinand was lucky to escape with a yellow card after bringing down Aiyegbeni Yakubu in the box.

Unsworth made no mistake with his penalty, shooting straight down the middle to beat Roy Carroll.

United laid siege to Shaka Hislop's goal but got caught on the counter-attack by Yakubu. The Nigerian took on Ferdinand and beat Carroll with a deflected shot that went over the Northern Ireland keeper's head.

"We beat United (1-0) here last year but today's performance was better," said Redknapp.

"They are a better team. They've got Rio Ferdinand back and Wayne Rooney playing for them.

"For us to beat them is a magnificent performance. We held on for grim life last time but today we always looked dangerous. We are full of pace up front and can give anybody a problem here. I thought we deserved it in the end."

Meanwhile United manager Alex Ferguson said: "We have to reflect on our own missed chances and at this level you can't afford to do that.

"It's a kick in the teeth after last Saturday's performance. We've lost a great chance."

Chelsea closed the gap on the Gunners to goal difference as they crushed the Baggies in the Midlands club's first match under caretaker-manager Frank Burrows after Gary Megson's acrimonious departure on Tuesday.

Frank Lampard's corner found John Terry at the far post and the England defender headed back across goal for William Gallas to tap in from two yards out just before half time.

Netherlands winger Arjen Robben hit the post before Eidur Gudjohnsen added a second in the 51st minute, heading in Damien Duff's cross.

Zoltan Gera pulled one back after 56 minutes but Ireland winger Duff snuffed out any hopes of a revival with Chelsea's third three minutes later, nutmegging goalkeeper Russell Hoult.

Lampard added the fourth with nine minutes remaining to add to the gloom at The Hawthorns.

"The first half was too bad to be true," said Chelsea manager Jose Mourinho. "We were lucky to be 1-0 at half-time but the second half was beautiful.

"It was a fantastic day with United losing and Arsenal dropping a point."

High-fliers Everton were held to a 1-1 draw by Aston Villa at Goodison Park.

Lee Hendrie hit an unstoppable shot from 20 yards into the top left corner of Nigel Martyn's goal in the 26th minute but the visitors' lead lasted just seven minutes before Everton's top scorer Marcus Bent equalised.

The forward hit his fourth Premiership goal of the season, chipping over Thomas Sorensen.

Blackburn moved off the bottom with a 2-2 draw at home to Liverpool.

But the match was overshadowed by the sight of Liverpool's French striker Djibril Cisse being stretchered off with a suspected broken leg in the 38th minute.

"I don't know. I have to talk to the doctor," said Liverpool manager Rafael Benitez when asked afterwards about Cisse's condition.

Former Birmingham striker Andy Johnson returned to haunt his old club as Crystal Palace stole a 1-0 victory at St Andrews.

Birmingham dominated the match between the two Premiership strugglers but Johnson scored with the Eagles' only shot on target to gift them their first away victory back in the top flight.

Middlesbrough beat Charlton 2-1 at The Valley and Fulham condemned Tottenham to a third straight Premiership defeat thanks to goals from Luis Boa Morte and Andy Cole at Craven Cottage.