Exeter boss Rob Baxter admitted his side put themselves under unnecessary pressure in their 44-29 Heineken Cup victory over Cardiff Blues.
The Chiefs had raced into a 41-3 lead before having two men sent to the sin-bin in the final quarter, when they shipped four tries.
"I think it doesn't matter who you play, when you go down to 13 men you put yourself under a bit of pressure and we got ourselves down to 13 men pretty unnecessarily," said Baxter.
"That flipped the whole game. Going down to 13 men, you are going to struggle a little."
Baxter was thankful, therefore, for the efforts of his players before the break, as they picked up where they left off after last weekend's Aviva Premiership victory at Gloucester.
"In the first half we played with real intent and the attitude that we took on to the pitch following last week was absolutely fantastic - not just a good attitude to attack the game but also the physicality and strength of the carries.
"Obviously the battle for us is to keep the quality for longer periods and when you end up on the defensive side, you don't end up conceding a couple of relatively soft penalties for a knock-on and an across-the-chest tackle.
"To give up a couple of those when you don't need to is a bit frustrating."
Cardiff host reigning Heineken Cup champions Toulon and the Blues' director of rugby Phil Davies will be keen to avoid a repeat of Sunday's first-half horror show.
"We talked at half-time," he said. "We didn't do anything that we said we would do, particularly for our kicking game and, that gave them too many opportunities to come back at us.
"I think we had to make 100 tackles and we missed 20 and that is not good enough at this level.
"We have to give Exeter credit for the way that they played but in the second half we were a bit more like it.
"They are a good attacking side but we came back second half to score those four tries.
"The first half was gone and we had to something about it - which we did and got some points back on the board.
"We had far more control on the game in the second half, far more field position. To get four tries was pleasing to get that point in the end to give us some momentum going in to next week.
"We'll fix up what we need to fix and we will go in to Toulon with a bit of momentum."
You can watch the Heineken Cup live on Sky Sports - the second round of pool games begins this Friday with Saracens v Toulouse on Sky Sports 1HD at 7.30pm.