Villa's group-stage opener at Club Brugge on Tuesday marks the start of a second season in Europe's premier competition under Unai Emery, and Buendía is one of only five players who started May's Europa League final victory over SC Freiburg to have remained at the club through a summer of major squad turnover.
The Argentine scored a stunning second goal in the 3-0 win in Istanbul, one of 11 he managed in all competitions last season, his best return since arriving from Norwich City in a club-record deal in the summer of 2021.
That campaign followed a difficult period in which an ACL injury ruled him out of the entire 2023/24 season and hampered his involvement during the first half of Villa's maiden Champions League campaign the following year, before he spent time on loan at Bayer Leverkusen. Villa's return to Europe's top table two seasons ago was their first since 1982/83, and Tuesday's trip to Belgium begins a second campaign that will be played out with a squad transformed by summer recruitment.
"The comeback was very important for me. I worked hard to stay and to help the team be successful, like we were last season," Buendía said.
"The same goes for this year. I want to be important, and I work every day for it. I also want to help the new players who joined the club to be successful together."
Ten new signings have arrived at Villa Park over the summer, meaning Buendía and his more established teammates have had to quickly integrate a substantially reshaped squad.
"Our job is to help the new players settle. The structure is there, and it doesn't matter how many players change because we have a clear philosophy and structure," he said. "The analysis for each game is clear, and tomorrow we have a great test in European competition. Playing away is always difficult, so the mentality has to be the same as it has been in the last few years: to be winners."
Asked about the wave of departures from last season's title-winning squad, Buendía struck a reflective tone. "It is not easy because we shared many years together and had many experiences, and in football things change constantly," he said.
"Now we have new experiences with players like Goretzka, and young talents who have played for big teams. The future is clear: these players are in a great place to develop and improve. They are good players in the present, and they can be huge players in the future for the next years at the club."