Morientes on the double
The Spaniard scored a fine first-half header and then a predatory close-range strike in the second period to give Liverpool control of the tie ahead of the return at Anfield on August 23.
Strike partner Djibril Cisse put Liverpool ahead with his fourth goal in five European matches this summer, but after Morientes' first, the Bulgarians hit back with a close range header seconds before the break from Velizar Dimitrov.