After last year's knee injury, the Argentina midfielder is getting closer to his very best and struck in Sunday's win against Fulham.
Recalling his situation over the summer, Buendia said: "I have been getting better and better and getting back to getting the confidence to play regularly.
"We had a clear meeting with the club and coaches to get the idea together.
"Always it was my preference to stay here because I really feel this club is my home and I feel myself close with everyone at the club and the fans because I think I can help this club to be even better in the future.
"We were really clear and together what he wants from me and what I can do for the team. Obviously, I want to help as much as possible the team to be successful.
"From the first moment I came to pre-season I worked really hard to get in the best shape. I felt quite well in pre-season, getting back with the team because the last months I had been on loan and we had not played together for a while.
"I had to get back in the rhythm of the team and the idea and philosophy of this club. I was feeling well, helping the team in pre-season and then also helping in the Premier League."