ISTANBUL (AP) — Cristiano Ronaldo aims to polish off Galatasaray and ease Real Madrid into the Champions League semifinals, holding a commanding 3-0 advantage heading into Tuesday's meeting in Istanbul.

Ronaldo leads Europe's top-tier competition with nine goals in nine outings. And with Galatasaray needing to score early and often, the prolific Portugal forward will likely enjoy ample chances to add to his tally.

"If we go with the ambition to score a goal, we will go through fine," he said.

Ronaldo opened last week's first leg with a delicate chip shot, and he needed just 45 minutes on Saturday to net his 46th goal this season in all competitions and set up another in Madrid's 5-1 rout of Levante in the Spanish league.

The last time Madrid lost by three goals or more in the Champions League was in 2008-09, when it fell 4-0 at Liverpool. Barring a similar upset by the hosts, nine-time champion Madrid is on course to reach its 24th semifinal.

"After our first meeting I told my players that a team who won the first match 3-0 may lose the second by the same result," said Madrid coach Jose Mourinho. "I said anything is possible and we must be very careful against Galatasaray. We have worked on the different defensive formations of Galatasaray.

"In the first game, they started the match with a four-man defense and switched to three in the second half. We worked on measures against both styles."

Madrid will be without midfielder Xabi Alonso and center back Sergio Ramos, who will be serving a one-match suspension for accumulation of yellow cards. Backup playmaker Kaka was left out of the squad for health reasons, and Pepe is in doubt with a pulled hamstring.

Young France defender Raphael Varane will likely replace Ramos, and Mourinho said Raul Albiol will play if Pepe isn't fit, while Alonso's absence could be filled by Luka Modric.

Mourinho has designated Diego Lopez as his starting goalkeeper, meaning Spain captain Iker Casillas will watch from the dugout for the second straight match since recovering from a broken hand.

Galatasaray will be without suspended striker Burak Yilmaz and his team-high eight goals in the tournament. Turkish leaders' hopes will largely rest on former Mourinho charges Didier Drogba and Wesley Sneijder.

Coach Fatih Terim's attack-minded game plan backfired for Galatasaray in the first game, as Madrid's scoring trio of Ronaldo, Karim Benzema, and Gonzalo Higuain all took full advantage of its exposed defense.

Terim said his team would be more focused on having a good showing than pulling off an epic comeback.

"Anything is possible in football, but when you are playing against Real Madrid things are not so easy," said Terim. "Galatasaray will try everything. I am sure about the ambition and enthusiasm of my players. We have prepared ourselves for any kind of result.

"We will play an entertaining game for our fans. The result will not be important."