LONDON: Manchester United swept back into the Champions League final as the holders produced a stunning 3-1 win over Arsenal in their semi-final second leg.

Sir Alex Ferguson's side arrived at the Emirates Stadium holding only a slender 1-0 lead from last week's first leg, but United scored twice in the first 11 minutes to set up a 4-1 aggregate triumph that booked their place in the final against Chelsea or Barcelona, who meet in their decider Wednesday.

Ferguson said that he had been pleased with his side's display.

"Obviously we got a big break for the first goal with the lad (Kieran Gibbs) slipping and Park Ji-Sung took advantage. However, in terms of how we played and our confidence and willingness to run it was overall a terrific display," said Ferguson.

United, who beat Chelsea in last year's final, were given a helping hand from Arsenal as South Korea winger Park Ji-Sung punished an embarrassing slip from Kieran Gibbs to open the scoring.

Cristiano Ronaldo then deceived Manuel Almunia with a long-range free-kick, and the Portuguese striker put the result beyond doubt when he added his second goal after half-time.

"I think I am back to my best, yes," said Ronaldo.

"Certainly in the last few games. But I always try to play good all the time.

"Sometimes it is not possible"

Arsenal barely tested United keeper Edwin van der Sar until Robin van Persie converted a late penalty after Darren Fletcher was sent off, ruling him out of the final, for a foul on Cesc Fabregas.

Ferguson was upset for the Scotland star.

"I think he was unlucky, because the ball certainly moved in a different direction after the contact in the area. He was terribly unlucky.

"However, the referee (Roberto Rosetti, who took charge of the Euro 2008 final) is one of the best in Europe. Darren would probably have played a large part in the final."

Even that couldn't detract from a fantastic display from United, who are the first defending champions to reach the final since Juventus in 1997.

They were simply outstanding and exposed the flaws in Arsene Wenger's inexperienced, injury-hit team with ruthless efficiency.

Wenger admits he will consider overhauling Arsenal's young squad after the Gunners were taught a Champions League lesson by Manchester United.

"What we do next is a hard question to answer. I'm too disappointed now. I need to take some distance with this season," Wenger said.

"We have gone 21 games unbeaten in the league but in the games that mattered like the FA Cup semi-final against Chelsea and this defeat to United we didn't do enough to win and we need to think about that."

After opting against multi-million pounds bids for Aston Villa's Gareth Barry and Liverpool's Xabi Alonso earlier this season, Wenger has been left with a midfield painfully short of a holding player to partner Cesc Fabregas.

Addressing that concern is only the start of Wenger's to-do list as he faces up to a fourth successive season without silverware.

No team has retained the trophy in the Champions League era, but United are hitting new heights and, with the Club World Cup and League Cup already won and the Premier League within touching distance, Ferguson and company are close to a memorable quadruple.

Arsenal were fortunate to be trailing by just one goal after a timid display at Old Trafford and the onus was on Wenger's side to make a fast start.

For once the normally subdued Emirates crowd were at fever pitch, but Ferguson had talked up United's intention to press for a crucial away goal and they were true to his word.

In the eighth minute, Anderson slipped a pass to Ronaldo down the left and the Portugal winger proved he had adapted to his new role as a lone forward by finding space in the penalty area to whip in a low cross.

Even then Arsenal should have cleared the danger but Gibbs, a teenage midfielder pressed into service at left-back in the absence of Gael Clichy, slipped over and could only watch from a prone position as Park took a touch before guiding his shot past Almunia.

As Ferguson and his staff danced a jubilant jig you could feel the momentum draining from Arsenal. There was worse to come three minutes later.

When van Persie fouled Ronaldo way out on the right flank, there appeared little danger.

But Almunia had reckoned without Ronaldo's flair for the unexpected. Ronaldo had scored from 40 yards to beat Porto in the last round and, from a similar distance, he took aim and launched a thunderous strike towards Almunia, who appeared to lose sight of the ball as it flashed past him at the near post.

Wenger sat ashen-faced on the bench as Arsenal's proud record of 27 home European matches without defeat fell apart, and the match had barely begun.

United were rampant and it took a superb finger-tip save from Almunia to stop Wayne Rooney curling in a third goal.

The visitors continued to counter-attack imperiously after half-time and in the 61st minute Ronaldo capped a sublime break in clinical style.

He started the move with a backheel to Park, who cleverly spread play wide to Rooney on the left. Rooney's cross was perfectly weighted for Ronaldo to drive past Almunia.

Game over, and Ferguson could even afford the luxury of substituting Rooney and Patrice Evra to ensure the duo didn't earn a booking which would have ruled them out of the final - Fletcher was not to be so lucky.