Saracens director of rugby Mark McCall blamed his side's two yellow cards and high penalty count for their loss to Exeter on Sunday.
Kelly Brown spent 10 minutes in the sin-bin in the first half and Chiefs wing Sireli Naqelevuki scored the game's only try in the second period while Saracens were down to 14 men after Chris Ashton saw yellow for charging into a ruck and shoulder-barging Exeter flanker James Phillips.
McCall, whose side climbed to third spot despite the defeat thanks to their losing bonus point, said the Ashton offence came at a key time.
"The fact that they scored a try during that sin-bin may have been our downfall. It was a difficult game in the conditions but their fundamentals were much better than ours," said McCall.
"You can't afford to come to a place like Sandy Park and lose two men to the sin-bin. On top of that we gave away a number of other penalties which had consequences in the match - something that we had prided ourselves on wasn't as good today.
"Our yellow cards and our penalty count just weren't good enough.
"I think Exeter were much better than us. Our set piece in the first half in particular wasn't good enough and we gave a lot of penalties away," added McCall.
"I didn't have a great view of Chris' yellow card but it was a rash act and the consequences of that are pretty big in a game like this.
"There was a lot of space out there and they scored a try down his wing and ultimately that is what lost us the game.
"We came to Exeter with hopes but we faced a very good Exeter team who rolled their sleeves up in difficult conditions."
Meanwhile, Exeter head coach Rob Baxter felt his team were good value for their 14-12 victory which lifted the Chiefs to fifth place in the Premiership table.
Sarries applied pressure until final whistle and looked like snatching the game as they tried to set up replacement fly-half Charlie Hodgson for a drop-goal attempt but ultimately failed.
"It was one of those scenarios - the clock is running down, and with a team like Saracens inside your own 22 you think this could go either way," he said.
"We'd managed to stop them a few times with some good sets of defence but, to be fair, it was difficult to play a lot of phases of play in the conditions. So I was there thinking, 'come on boys, don't give up the penalty - make them have to play several phases'. And that's what we did and the error came.
"So I think that we deserved it [the win] and I would have been disappointed if we had lost it by a point or two at the end.
"I am a big believer that you get what you deserve out of rugby and today we probably deserved it and I'd like to think the win shows that."