Cristiano Ronaldo returned to goal-scoring form and Marcelo was also on target as holders Real Madrid opened their Champions League last-16 tie with a 2-0 win at Schalke.
Ronaldo ended a rare drought of three games by heading Real ahead in the first half at the Veltins-Arena before Marcelo made victory safe with a fine second late on.
Schalke proved much tougher opposition than last year, when they were thrashed 6-1 at the same stage by the same opponents, and rattled the bar at 1-0 down through Felix Platte.
Timon Wellenreuther, a 19-year-old goalkeeper pressed into action due to injuries, also impressed but ultimately Roberto Di Matteo's side could not deny Real a 10th successive win in the competition.
Schalke, deploying a five-man defence, made an encouraging start and contained their visitors in the early stages.
They also had some early chances as Dennis Aogo fired a free-kick into the wall and then missed the target after being picked out by Marco Hoger.
Former Real striker Klaas-Jan Huntelaar had the first serious effort on goal from distance but Iker Casillas saved well to his left.
It then seemed Schalke's good early work had been undone as Real grabbed the lead through Ronaldo after 26 minutes.
Ronaldo, who had shot wastefully wide from distance moments earlier, timed his run superbly to meet Dani Carvajal's curling cross and head past Wellenreuther.
It was the world player of the year's sixth goal in seven Champions League appearances and sent an emphatic answer to recent critics of his form.
Real almost had a second soon after as Karim Benzema broke through but Wellenreuther just got enough on his shot.
Things got worse for Schalke as Huntelaar was then forced off injured after a clash with Raphael Varane.
Ronaldo wanted a second from a 30-yard free kick before the break but Wellenreuther tipped away his curling effort.
Schalke tried to force their way back into the game in the second half but Kevin-Prince Boateng spurned a good opportunity when he shot over.
Real threatened again when Gareth Bale neatly combined with Isco outside the area but the Spaniard shot over.
Schalke served the champions a warning after 74 minutes as substitute Platte struck the crossbar with a fierce effort. Atsuto Uchida was quick to the rebound but could not trouble Casillas.
That prompted Real to step up the tempo and they took a firm grip on the tie 11 minutes from time as Ronaldo cut in from the left and beat two defenders to find Marcelo on the edge of the area.
The Brazilian gave the Germans no chance as he took a touch and clipped a superb shot over Wellenreuther.
The goal deflated Schalke, who then switched to damage-limitation mode for the remainder of the match. They had not been outplayed like last season but were still left facing a huge hurdle at the Bernabeu in the second leg.