Leo Cullen admitted frustration was the overwhelming emotion as Leinster let an eight-point lead slip against Ulster in their URC derby on Saturday night.
The 23-21 defeat means Leinster are third in the table and unable to improve on that position unless Munster and Bulls both fail to win their last games.
The visitors conceded first but led from the 29th minute until the 79th when John Cooney landed a long-distance penalty.
Depending on how other results go they are unlikely to host a potential semi-final or final.
"Frustrating I think, I thought there was a lot of good effort in the game," said the head coach (below).
"We had a plenty of chances, we were ahead right until the very end so, listen, there's probably good learning in how we manage some of that last 20 minutes.
"We had plenty of opportunities, we had them in the far corner, the maul is going forward well and we give away the penalty.
"We had some other opportunities as well, anyway it's just a frustrating game.
"You couldn't fault the effort, the effort was great,
"It was great to get ourselves in a good position, but we need to be better in terms of how we execute certain things."
Leading by a point after Jacob Stockdale's intercept try and Cooney’s conversion, Leinster, with James Ryan captaining the side on his return from a bicep injury, turned down a shot at goal in favour of a kick to the corner, from which Ulster turned over the ball.
"[It’s the] feel of the game. The players were out there," he said of the decision.
"I don't mind that much, maybe if it's a knockout game it's different because you can go for a four-try bonus point, there's other factors at play today versus a final.
"I don't mind that, everyone judges on the outcome sometimes, but when you're in the moment, you can score a fourth try and get a bonus point, go eight points in front and I wouldn't get bogged down in it."
Centre Charlie Ngatai, who scored Leinster’s first try, and Tommy O’Brien both left injured in the first half, while Ryan, Hugo Keenan and Will Connors all came through the game unscathed.
"Charlie got a bang on the shoulder, we'll see how he is," added Cullen, whose side face Toulouse in the European final on Saturday (2.45pm, live on RTÉ).
"Tommy pulled up with his hamstring, we took him off before it got worse so we'll see how he is.
"it's positive getting some guys back who hadn't played for a while, they got through some decent time."
Meanwhile, Ulster boss Richie Murphy (above) said he was delighted with his team’s character to stick in the game.
The hosts are in sixth position and now guaranteed to finish no worse than eighth.
"I know that loads of things happened today," said Murphy, who was appointed permanent head coach earlier in the week.
"Coming into the game I thought if we got a couple of points we’d probably be in the play-offs but then with everyone else winning we needed to win tonight.
"It’s very satisfying, the crowd were incredible, getting in behind the team and we feel like we are getting better over the last couple of weeks, compared to where we started, you can see things coming together.
"That was probably our most complete performance even though we still had loads of mistakes."
On Cooney’s late penalty to win the game, the former Ireland Under-20s boss said: "Made for John. Two minutes to go, any kicker, they are the kicks you dream of, but you don’t really want, but John’s probably a bit different, he probably does want them.
"He stepped up, no problem. I think he’s on a massive run of consecutive kicks.
"His goalkicking is really top class and when he was stepping up to it I didn’t fear he wouldn’t get it."
Ulster face Munster away in the final round in two weeks’ time, while Leinster host Connacht.
Watch highlights of the weekend's action on Against the Head, 8pm, RTÉ2 and RTÉ Player
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