Pep Guardiola has described his decision to leave Gerard Pique out of the squad for the 3-1 victory at Bayer Leverkusen as a "technical decision" and said he remains a key player for the club.
Pique was a surprising absentee from the matchday squad on Tuesday night, with Javier Mascherano playing at centre-back alongside Carles Puyol and 21-year-old academy graduate Marc Bartra providing cover on the bench.
"I had to pick an 18-man squad," Guradiola told the post-match press conference. "Mascherano is suspended for the game against Valencia on Sunday, so I couldn't afford to lose Gerard. I also wanted to bring in Bartra, who we'll need in the near future.
"Pique knows I love him. He's not angry about it. He knows he's untouchable and is very important for us."
Xavi also missed out on a place in the squad as a result of a calf injury, with Guardiola saying he has been suffering with the injury for several days. "He is training a little, but he's not fit," he said.
Despite the absentees, Barcelona were able to emerge from the first leg at the BayArena with a two-goal lead courtesy of a brace from Alexis Sanchez and a late strike from Lionel Messi, and Guardiola was happy with his team's efforts.
"Overall we are very satisfied with the first leg, although the second half was a warning for us for the second leg," he said. "Germans have great self-confidence, but to score three times away from home is great."