Eidur Gudjohnsen and Javier Saviola both scored goals while stepping in for the injured Eto'o, and Rijkaard was quick to praise their efforts.
"It's always important to be able to score goals, I'm happy for both Gudjohnsen and Saviola, their goals helped to calm the nerves of the team," Rijkaard was quoted a saying by Barcelona's website.
Beyond the goals themselves, the Dutch boss was exuberant Gudjohnsen's impressive showing considering he did not play the full game.
"Gudjohnsen has not played a full 90 minutes yet, but worked hard to find his goal. His goal, the second for Barca, was important for him and the team," said Rijkaard.
Gudjohnsen took to the starting line with a fury and admitted to doing the best he could with the opportunities he was presented after Eto'o was ruled out for five months through injury.
"I had a good game and scored a goal, I'm happy and I hope to continue in the same way, it's my big chance and I want to take full advantage of it," he said.
Rijkaard also noted that the ejection of Bilbao player defender Casas early on for fouling Gudjohnsen "changed the game".