MADRID, Spain -- Cristiano Ronaldo scored a record equaling goal before exiting to injury as Real Madrid beat Borussia Dortmund 3-0 on Wednesday to take a big step toward the Champions League semifinals.

Ronaldo netted his 14th goal of the season in Europe's top competition to give Madrid a clear advantage ahead of next week's quarterfinal return leg in Germany. But it came at a price as the Portugal forward, who came into the first-leg nursing a sore left knee, came off in the 80th minute.

Gareth Bale scored early and Isco added another before the half hour mark at the Santiago Bernabeu Stadium.

"Ronaldo has a problem with his knee but at this moment I'm not worried about it," Madrid coach Carlo Ancelotti said.

The Spaniards opened against Dortmund as the Germans had against them in the semifinals last season -- when they thrashed Madrid 4-1 en route to reaching the final with a 4-3 victory on aggregate.

In Wednesday's other quarterfinal first leg, Paris Saint-Germain beat Chelsea 3-1 in the French capital.

Madrid certainly didn't need inspiration after last seasons' loss to Dortmund, which was without suspended striker Robert Lewandowski and five more regulars to injury as it fielded just four of the players present in last season's 4-1 win.

"The goals we gave up tonight were not because of this," Dortmund coach Juergen Klopp said. "It was too easy (for them), and that's not what we wanted. We made some mistakes and we were punished."

The energetic start saw Bale nearly miss Dani Carvajal's short pass inside the area before stretching to toe poke his fifth goal of the competition under goalkeeper Roman Weidenfeller after just three minutes.

Weidenfeller was sharp despite Madrid's early onslaught as he punched free kicks from Ronaldo and Bale over the bar. He also stayed in the game despite wincing in pain after Marco Reus made a clearance that also connected with the 'keeper's hands.

With forward Angel Di Maria out to a gastro virus, Isco showed good poise to gather a loose ball in front of the area and slide home a low shot for 2-0 in the 27th minute.

The Spain midfielder's goal was just the boost Madrid needed as Dortmund began to find its rhythm, with Kevin Grosskreutz forcing Madrid goalkeeper Iker Casillas into a low stop in the 33rd.

Ronaldo, playing in his 100th Champions League game, was clearly eager to match the record 14 goals scored by Lionel Messi in one Champions League campaign.

Luka Modric made it happen as the Croat pounced on a poor Dortmund pass deep in its own area in the 57th minute and picked out Ronaldo, who dribbled around Weidenfeller for his 45th goal of the season. Jose Altafini also scored 14 goals in the 1962/63 European Cup campaign for AC Milan.

"We did what we prepared for well," Ancelotti said. "We used a lot of energy in the first half and were tired. So we dropped the team back a little in the second half -- while looking to score on the counter."

While Ronaldo and Karim Benzema continued to threaten Dortmund's goal, Madrid was fortunate not to concede under pressure as Pepe blocked Reus' shot from inside the area after Casillas failed to control a cross. Madrid's defence blocked several Dortmund shots during the final stages.

"You have to do the right tactical things against the best teams in the world. We can do better than we did tonight," said Klopp, who rued the late misses. "(Losing) 3-0 you are not cool, you are not confident, you are under pressure and you are not confident in the box. We had chances."

Madrid, which is vying for a record 10th European Cup, is now on the cusp of a fourth straight appearance in the semifinals -- a welcome lift after a difficult run in the Spanish league.

In Tuesday's matches, defending champion Bayern Munich drew 1-1 at Manchester United, and Atletico Madrid drew 1-1 at Barcelona.