And although his side conceded 18 points and scored just 14 after opposing centre Steve Shingler was sent off midway through the first half, picking up a second successive win was by far the most important outcome as far as Burnell was concerned.
"When we arrived at the stadium today, if somebody had said to me 'it's not going to be the best performance and it's going to be pretty tight but you'll win the game', we would have taken that," said Burnell, whose men shocked Racing Metro 92 in Round 1.
"It perhaps wasn't as good a performance as it was out in Paris last week, but it was a win and we can't lose sight of that fact. That's what it's all about.
"When we started the game, we were very comfortable against 15 men. We had a good intensity, like we did against Racing. We were conscious that London Irish would try and run and attack us from all areas yet in the second half they kicked everything.
"As soon as their player got sent off, my first thought was back to Gloucester at Kingsholm in 2009 when Tom James got sent off for us in front of a full house. Our intensity and our game plan just seemed to change that day and we won up there with 14 men.
"My thought process was that London Irish's game plan would be similar to ours that day and that was the case. They bogged us down and kicked a lot of ball. We got caught in the middle channel and they threw a lot of numbers in there and managed to slow our ball down.
"Fortunately for us, we won up in Gloucester but London Irish didn't win down here."