Mark Allen said he as good as lost his World Championship second-round meeting with qualifier Kyren Wilson in a disastrous opening session.
The Northern Irishman trailed 7-1, and despite twice getting to within two frames, Wilson won through 13-9.
"The comeback probably looked on a couple of times at 7-5 and 11-9. I had two chances to push on," said Allen.
"It's true that you can't win it in the first session but you can lose it, and that's where I lost that match."
An astonishing game saw Allen trail 7-0 and then win five in a row to get back to 7-5 on Sunday evening, before losing the next four to end the session 11-5 behind.
"He deserved his 7-1 lead and played superb snooker," world number seven Allen said. "Kyren thoroughly outplayed me. He didn't put a foot wrong in that session."
The topsy-turvy nature continued on Monday with both men refusing to change their attacking, aggressive style.
Allen won the first four frames to make it 11-9 and bring hope of an astonishing fightback, with breaks of 86, 103 and 64.
But Wilson, making just his second Crucible appearance, showed he has the temperament to equal his talent by winning a scrappy penultimate frame before sealing victory with a fine 71 under intense pressure.
Crazy, crazy game
Wilson said it was "probably the strangest match he has every played", describing it as "crazy".
Allen was pleased with his efforts after such a bad beginning. But the Antrim man took little consolation after failing to reach the last eight for the fifth year in succession.
"I've always been a fighter so I wasn't going to give up out there," Allen added.
"I got close enough and looking back people will say you did well to get back into it but I'm sitting here as a second-round loser once again and that's a disappointment that I have to take back and look at."
Trying to win the mind games
Allen said he employed every tactic he could to try to get back in the match.
"He held himself together really really well," Allen added.
"When you're 7-0 down you have to try other things other than potting balls and I tried my best to get at him and get under his skin but it didn't work. I feel my game is in good shape but the first session just cost me.
"I set my season out to win the World Championship and I haven't done that so it's a waste of a year really."
"I put him under a lot of pressure and he handled everything. That's the sign of a top player."