Marcelino insisted Villarreal "did not beat Liverpool by being lucky" after the Spanish outfit claimed a last-gasp 1-0 win in their Europa League semi-final first leg.
Adrian's 92nd-minute goal was all that separated the two teams at the El Madrigal on Thursday.
With time running out and the match petering out for a draw, Denis Suarez teed up team-mate Adrian for a simple finish, capping a fine counter-attacking move.
However, Marcelino insisted Villarreal were deserved winners.
"Until the final whistle you can score or concede a goal and this time we were lucky enough to score in the very last minute," Marcelino said.
"We managed a good result, but we don't know if it will be enough or not until the end of the tie.
"It was not an unfair result and we didn't beat Liverpool by being lucky."
The Villarreal coach added: "We knew it was going to be a very complicated and even, with a lot of rhythm and intensity game. Fortunately we got a goal when the match ended.
"Overall we are very satisfied with the game, We played a very good game at a competitive level. We have defended with order. Very proud of these players. Still far from the end, but closer than we were at 88 minutes."
Villarreal will head to Anfield next week in a good position to reach their first major European final, but Adrian knows the tie is far from over.
"At Anfield they are a very good team. We have to top it off there," Adrian said.
"Yes, it was very important to leave a clean sheet and try to win. We had to leverage that we played at home.
"The lead is good, but we know it will be difficult at Anfield. They are very strong there. We have done well but we have to finish it in Liverpool."