A capacity 17,498 crowd saw Tigers grab a winning bonus point following tries by Sam Vesty, Seru Rabeni, Martin Castrogiovanni and Julian White.
“I am happy with the win because we had to come back from two defeats away from home so this was important to us,” said head coach Loffreda who made 12 changes to the side beaten at Sale Sharks on the weekend before Christmas.
“The team gelled together well. They all had a big responsibility today because it was a must-win game for us. They took the responsibility and the opportunity and they did it really well. We are very pleased with that.
“The win is important to give confidence to this team and to some of the players that were not in the team for a while. They did really well.
“Maybe in the first half we lost the initiative for 20 or 25 minutes but we got it back and in the second half we were better because we showed good ball control and dominated territory.
“The bonus point is important too. The win is encouraging for everybody at the club, including the supporters. But it is a long season , we have to be patient, we have to go game by game and try to improve with each game.”
Irish director of rugby Brian Smith said: “It is frustrating because at 20-17 we were still in the game. We had the wind with us in the second half, we kicked well for field position and, looking at it now, we are wondering how we did not take anything out of the game.
“It is disappointing, but we are very proud of the performance, particularly as we lost our captain Bob Casey to illness on the morning of the game and had a few disruptions during the week. We weathered the storm in the first half, we played the conditions well in the second half, but this is Leicester Tigers and Welford Road, and it is not an easy place to win.”