Real won 2-0 thanks to goals from Eder Militao and Kylian Mbappe, with Vini Jr reinstated to the starting XI.
Xabi said afterwards, "Vinicius? Today (yesterday) he was only missing a goal. When he was at his best, I substituted him and could have waited a bit longer, but I thought it was better to bring on fresh legs.
"He and Franco (Mastantuono) wanted to continue, but there are still a lot of games to play. He hit the post, which was a shame. I'm happy with the game they both played, and sometimes you need fresh legs because the schedule is very demanding."
Xabi also said: "It was a solid victory, more than a brilliant one, but it was a positive one.
"We controlled the game and didn't have any stressful situations, like conceding goals or being sent off. They're not the most fun, but I like them. We controlled the second half well and had chances to score the third. It's a victory that allows us to continue growing and focus on Tuesday's match against Levante."