The 24-year-old Everton full-back's performance was one of the bright spots in Wednesday night's 1-0 friendly defeat by Greece at the Aviva Stadium as Trapattoni gave some of his young players a chance. Coleman lined up at right-back and combined repeatedly with winger Robbie Brady to cause the Greeks problems.
Trapattoni said: "Coleman was fantastic, he was the man of the match. We know him and we have told him he is important to us for the future."
The Ireland manager added: "I have said many times, the midfield of our team is not only the four midfielders, we have two more, the right and left-backs.
"Seamus is fast, he can recover the ball, he has a good personality and at this moment, he has a very good future."
while Trapattoni was disappointed with the result, he was pleased with the players he brought into the team with Norwich midfielder Wes Hoolahan winning a second senior cap as a half-time substitute.
The Italian said: "He [Hoolahan] was very good. The confirmed the quality we know he has.
"He's a good option maybe if we need to have one striker and at the moment, we have no other players in this position.
"Football is about results, but we had some good situations and three or four of the players showed their personality in this difficult game.
"It was very important to have a good performance after the disappointment against Germany. You can see a progression."