Inter Milan produced a stunning performance to beat holders Barcelona 3-1 in the Champions League semifinal, first leg at the San Siro on Tuesday.

Goals from Wesley Sneijder, Maicon and Diego Milito extinguished Pedro's opener for Barca and sent the nerazzuri faithful into raptures ahead of next week's second leg at the Camp Nou.

It was a tactical masterclass from Jose Mourinho as his team wiped out memories of the footballing lessons Barca gave them in the group stages back in September and November.

The Portuguese boss said even if his team don't reach the final in Madrid, he will be satisfied.

"It gives me great pride to say that we could go to Madrid to play the final or we will come home from Barcelona with our heads held high," he said.

"Obviously we'd be happy if we go to Madrid and if not we'd be disappointed but we know that we've done everything.

"When I arrived at Inter we had trouble just qualifying from the group stages, we didn't do well in this competition and had a fear of winning and people said we couldn't play in Europe.

"But now we've beaten the best team in the world and now Inter are a great Champions League team.

"If we don't win it this year, we'll win it next year or in two years time. We'll be in the semifinals and finals, we've changed."

Barcelona coach Pep Guardiola was magnanimous in defeat and refused to blame the team's 14-hour coach journey to get here for the loss.

"This can happen, especially when you're playing in the semifinal of the Champions League and against Inter Milan," he said.

"Of course it's not ideal losing like this but we can still do it.

"The result is not good, we gave away too many balls, we can do better. This wasn't our best game and Inter don't make it easy for you to play.

"I know they're tired but I'm not a medical expert and I can't say how much the journey affected them."

Mourinho picked an attacking line-up with three forwards plus playmaker Sneijder in midfield and from the off they demonstrated a willingness to take on the champions.

It was they who created the first clear-cut chance on 18 minutes as Samuel Eto'o curled a left-footer from outside the area that Victor Valdes failed to hold but Diego Milito fired the rebound straight across the face of goal.

Inter were looking relaxed and confident but a minute later they fell behind through some dreadful defending.

Former Inter left-back Maxwell ran far too easily down the left past three non-challenges, reaching the byline where he pulled the ball back and with Inter's defenders preoccupied by Zlatan Ibrahimovic in the centre, Pedro came in off the right flank to drill the ball home from 15 yards.

The hosts kept going about their task, though, and Sneijder slid a lovely pass to Milito in the inside left channel but again he dragged his shot just past the far post.

Yet on the half hour mark Inter got the equaliser they deserved as Maicon played Eto'o down the right, he pulled the ball back into the middle and Milito took it off Goran Pandev's foot but then fed it on to the unmarked Sneijder at the back post for a right-footed finish inside Valdes's near upright.

In that first half Barca had enjoyed almost 65 percent of the possession - but Inter were showing that their coach's assertion after the pair met in the group stages that you can play well without the ball, certainly rang true.

Mourinho had also said before kick-off that Barca were as good as they were back then but that Inter were much improved and their display bore that out.

Inter's first half had been impressive but they started the second at a canter with Pandev shedding off three players in midfield and then playing Milito behind the backline, the Argentine pulling the ball back for the charging Maicon to prod home his second goal in successive games, just three minutes in.

Messi finally woke up and got his first shot off on 53 minutes but Julio Cesar parried it and the Brazilian stopper had to be alert moments later to block a close-range Sergio Busquets header from a corner, although the Spaniard should have scored.

But Barca could not handle Inter's attacking flair and on 61 minutes Eto'o crossed from the right and Sneijder's poor header bounced up for Milito, arriving at the back post, to nod home.

Barca took total possession of the ball in the closing stages and Inter survived one scramble in the box as Lucio blocked Gerard Pique's prod from a tight angle on the line.