Osasuna all but booked their place in the semi-finals of the Uefa Cup with a 3-0 win at Bayer Leverkusen.
Goals from Carlos Cuellar, David Lopez and substitute Pierre Webo gave the Spaniards a resounding first leg victory.
Osasuna got off to a dream start in the very first minute when Cuellar headed home Lopez's corner to stun the home crowd.
The visitors almost grabbed a second goal six minutes later when Cuellar again got on the end of the corner, but he could not direct his header on target.
Bayer tried to rally and Andrei Voronin and Stefan Kiessling both went close with efforts from the edge of the box.
The home side started the second half on the front foot and they should have drawn level when Voronin played Juan in on goal, but Ricardo did well to keep out his close-range effort.
Lopez missed a glorious chance to double the lead on 71 minutes when he raced clear on goal only to see his attempted chip kept out by Rene Adler.
Seconds later Lopez made up for his earlier miss when Savo Milosevic teed him up inside the box and he drove his shot high into the net.
Two minutes later Osasuna grabbed a third goal when Milosevic played in Webo and with his first touch after coming on the striker coolly lobbed his shot over Adler to silence the BayArena.
Osasuna wasted good chances to add to their lead late on with Cuellar and Milosevic missing when well-placed.
The Spanish side will be confident of finishing off the job next week as they look to secure their first ever appearance in the semi-finals of a European competition.
Click on fixture for full match summary
Bayer Leverkusen 0-3 Osasuna