Buendia struck first inside the opening 20 minutes before Ollie Watkins sealed the win late on.
“As always, I try to get these positions,” he said.
“I really trust my shots and when I (saw) the possibility to find the far post I just went for it.
“It was a good goal. To help the team to start in this place to winning the game, put us in a really good position, so really happy.”
The 29-year-old added: “We know how strong they are here. They have their fans behind, they push, they like to press, they are a really strong team.
“We tried to find the spaces in behind, to be aware of the second balls, and I think we had many transitions where we (could have) hurt them more.
“I think we did a really strong performance, and I think we deserved the three points.”