The teams meet at this stage for the second season in succession, Barca having emerged with a 4-1 aggregate victory last time around.
Luis Enrique's men visit the Etihad Stadium on Tuesday, before the reverse fixture at Camp Nou three weeks later, and Messi predicts a tight tussle for a place in the next round.
"It is going to be a hard match when we face City again, just like last year," he said in an exclusive video interview with Perform. "They are a team with great players, who want to get to the quarter-finals.
"They have been trying to achieve for a long time. They have spent a lot of money to have a good team, bringing in good players.
"So they are going out to win, and it will be a very even match, where the finer details could prove important.
"I think that it will be a great match."
Asked whether he had discussed the fixture with Argentina team-mate and City striker Sergio Aguero, Messi revealed: "Yes, we talked when we saw each other, but only for a short time. We talked more about other things."
Barca are on an 11-match winning run in all competitions - sitting one point adrift of Liga leaders Real Madrid and holding a 3-1 advantage over Villarreal in their Copa del Rey semi-final - but Messi insists they can ill-afford to take their eye off the ball.
"We haven't won anything yet, so there is still a long way to go," he added. "There are still many months of competition left in La Liga and the Champions League and we still have to fight for a place in the Copa del Rey final, so I believe there is yet plenty of time to keep playing in this way in order to reach our goals."
