A solitary point separated the teams in Llanelli, where Louis Rees-Zammit’s late finish proved decisive in a 17-16 contest shaped as much by missed opportunities as by moments of quality.
But for Peel, the optimism stemmed from what the performance suggested about the Scarlets’ potential.
“I am proud of the effort, we really prepped well and the level of performance was good, it's just that key moments we need to improve,” he said, stressing that the display underlined the strides his squad has made.
“The boys will be gutted after that loss but the important thing is that we recover well and make sure we are ready for the next couple of weeks.”
Peel took some measure of comfort from belief, even as he acknowledged the fine margins that cost the Scarlets a victory on their European comeback.
“We played well in some good patches of the game and really put them under pressure with a couple of disallowed tries early on.
“They were a bit of a killer, in all honesty with the momentum swing of the game.
“But towards the end, I think there was some key moments where we had a couple of lineouts in their 22 that we didn’t convert and conversely, they had one that they did.
“That is the game at this level and those are the takeaways.
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“I am proud of the effort; it was huge from everyone.
“We really prepped well over the last couple of weeks. The level of performance was good; it’s just those key moments we need to improve on.
“The defensive shape and the overall gameplan [was good]. I thought we moved the ball well.”
Scarlets had every right to believe the match was theirs for the taking.
Viliame Mata caused major problems in the first half, touching down twice, but Gareth Davies’ sharp score and a composed second-half penalty from Sam Costelow nudged the hosts ahead.
With momentum swinging their way, Tom Rogers and Jac Davies both crossed — only for the TMO to intervene, ruling out tries for a knock-on and a forward pass in the build-up.
Peel did not hide his frustration at those turning points.
“It was bitterly disappointing in the end.
“We played well in some good patches and really put them under pressure with a couple of disallowed tries early on.
“Those were real killers especially the second try I thought it was a really good well worked try for us.”
He also addressed the controversy surrounding Mata’s yellow card for a shoulder charge to the head of Johnny Williams — a decision that could easily have resulted in a red.
“It could easily have been a red, yes,” said Peel.
“Complaining doesn't change the result. It is what it is.
“We will move on from there. It was disappointing to have a couple of tries, as they did as well, get pulled back.”
In the end, Bristol capitalised on their lone clear second-half opening, with Rees-Zammit sliding over in the corner.
It was hardly one for his career showreel, but it was enough to snatch victory for the visitors, who were made to work throughout.
Bristol director of rugby Pat Lam praised the Scarlets’ ferocity.
"It was exactly what we expected,” said Lam.
“I said to the boys that technically and tactically we know what we are going to do, but when you go to Wales you are going to get nothing for free, we would have to fight and earn everything.
"The pitch was quite heavy and fair play to the Scarlets, we saw what they did last week (when beating Glasgow). They have some quality players and knew we would have to really work hard.
"I love the fight, we had to hang in there. We've got that win and now we go hard next week against Pau."
Scarlets at least emerged with a losing bonus point — valuable in a pool that also includes defending champions Bordeaux-Bègles, who they visit next weekend.
And despite the defeat, Peel left Parc y Scarlets confident that his team’s level is high enough to compete with the very best.
The challenge now, as he made clear, is taking a performance that hinted at promise and turning it into a springboard.
