John Hughes felt his side let the game slip away from them as Inverness defeated Partick Thistle 2-1 to make the Scottish Cup quarter-finals.
The Highlanders dominated the first half but were in danger of letting their hosts secure a replay with a less than enthusing second-half display.
"We were very good in the first half, we di enough to score two or three goals," Hughes told BBC Scotland.
"It was a game of two halves, all Partick Thistle, they threw the kitchen sink at us but we stood solid and firm."
Marley Watkins and Greg Tansey scored in the opening period to give Inverness a two-goal cushion.
However, Lyle Taylor pulled one back for the hosts, and Daniel Seabourne almost snatched a last-minute equaliser with a header.
"On our first half performance it would have been an injustice had we not won the football match," said the Inverness boss.
"Some of the stuff we played in the first half, it was real good stuff. Dominated the game and should have been two or three goals up.
"That's my only disappointment, no-one in the second half was brave enough to get on the ball, two or three passes, and take the sting out of the game.
"All credit to Partick Thistle they gave it a real good go and we just held on.
"We never beat Partick Thistle, in fact they battered us last time we came here, but I was really confident coming here today.
"I knew the way the boys trained, the way we prepared the match, that we were going to be at it and that was the case in the first half.
"In the second half the game just run away from us but we showed resilience and character just to dig it out."
Partick Thistle manager Alan Archibald took the consolation of a better second-half performance but was disappointed overall with his side's display.
He said: "Inverness were much the better side in the first half and fully deserved their two-goal lead. We were very disappointing.
"Second half we got a reaction out of the lads, I was pleased with that, but we didn't do enough to go and get at least a draw.
"I think the two goals we lost were just down to us dwelling on the ball, taking too many touches. We said to them we couldn't do that on a bobbly pitch and to make sure we moved the ball quickly, and we didn't do that.
"It was not good enough, nowhere near good enough. Even if you're not playing well go and win your individual battle, that's what we asked them to do.
"It was a great incentive this year with so many top-flight teams going out and we didn't want to go out with a whimper."