The England international volleyed home soon after the restart to give City hope of an unlikely comeback after Liverpool had taken a three-goal lead in at the break.
Bernardo Silva reduced the deficit once again in the 91st minute, but it came too late for Pep Guardiola’s men to force extra time at Wembley Stadium.
Despite the setback, Grealish remains confident that City have both the quality and mentality to finish the season with domestic and European honours.
“Yes, 100% (we still believe we can win the Premier League and Champions League),” he told mancity.com afterwards.
“You go in there and look at the talent and experience that we have in that dressing room, I don’t think anyone else in the league has one like it.
“Our performances and where we are in the league speak for itself.
“We just have to pick ourselves up, go again and hopefully by the end of the season have the Premier League and the Champions League.
“That’s what you’ll get at Manchester City because you’re always in competitions come the end of the season, it’s always game after game.
“We’ll get ready, rest and recover and look forward to Wednesday back at the Etihad.”
Watch the full interview in the video above.