(CNN) -- Barcelona took a big step towards setting up a semifinal showdown with Spanish rivals Real Madrid by beating Shakhtar Donetsk 5-1 in the Champions League on Wednesday.
The Ukrainian champions are unbeaten at home in more than two years ahead of next week's return leg, but the 2009 titleholders took control of the quarterfinal with a typically dominant display in the Catalan capital to match Real's four-goal demolition of Tottenham on Tuesday.
Andres Iniesta, playing further forward than his usual midfield role, settled any signs of nerves for the home fans inside two minutes when he pounced to score after Lionel Messi's intended pass to strike partner David Villa was deflected into the 2010 World Cup match-winner's path.
The Spain star then set up Daniel Alves for the second goal in the 34th minute with a clever pass over the defense that the Brazilian fullback pushed wide of goalkeeper Andriy Pyatov and flicked into the net with the outside of his right foot.
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Alves turned provider eight minutes after halftime with a low corner that allowed central defender Gerard Pique to fire in a deflected shot after pulling back to lose his marker.
It was Pique's second goal in as many matches, having volleyed the winner from Alves' flicked-on corner against Villarreal on Saturday that put Barca eight points clear of Real in the La Liga title race.
Shakhtar reduced the deficit in the 59th minute when defender Yaroslav Rakitskiy stole in at the near post to put Darijo Srna's freekick past goalkeeper Victor Valdes with his knee.
But Pep Guardiola's team responded within 60 seconds as top scorer Messi surged towards the penalty area and teed up Seydou Keita, who smashed a superb left-foot shot into the top corner of the net.
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Brazilian striker Luiz Adriano almost made it 4-2 with nine minutes to play but his shot from a tight angle hit the post and bounced safely into the arms of a relieved Valdes.
Messi had the ball in the net soon after, but his provider Pedro -- who made his return from injury as a 70th-minute replacement for Villa -- was ruled to be offside.
However, the fifth goal came soon after when Alves made his way into the box and provided a perfect low cross for midfielder Xavi -- another player returning from injury -- to steal in unmarked and sidefoot into the net.
