Manchester United's two-goal hero Cristiano Ronaldo says he's back to his best after their Champions League success at Arsenal.

United beat Arsenal 3-1 at the Emirates Stadium tonight to secure a 4-1 aggregate success and will face Chelsea or Barcelona in Rome on May 27.

Ronaldo scored twice after Park Ji-sung's opener and when asked if he is now back to his best, the attacker told ITV1: "I think so, yes.

"In the last few games I have felt good, felt fit. This is a crucial time in the season and the best games are coming."

Ronaldo moved to spare Manuel Almunia's blushes by admitting his first goal, a 40-yard free-kick, swerved past the Arsenal stopper.

"The shot was quite difficult to save because the ball moved a little bit," he said. "I just try to do my best to put the ball in the net and it was a good goal."

Darren Fletcher's harsh sending off in the second half led to Robin van Persie's penalty-spot consolation and Ronaldo expressed sympathy for his team-mate, who will now miss the final.

"It is very disappointing, he deserves to be in the final because he is a fantastic player, he runs a lot and is a team player," said Ronaldo.

"He deserves to play in the final but this is football."