Adrian Lam's 'sorry' to fans after Wigan Warriors' 18-8 loss to Hull KR
He admits their performance wasn't good enough, comparing the intensity and quality of their display to a pre-season friendly.
The disappointment was amplified by the fact it was Wigan s first match in front of their home crowd in more than 15 months.
Lam said: "I'm disappointed. It was frustrating, we weren't connected as a team, we made too many mistake.
"There was effort there, no doubt about that, and I have to give credit to KR's defence, I don't want to take anything away from them.
"We got held up four times, there were three opportunities which didn't come off and some times you get a feel as a coach of, 'Here we go, it's going to be one of those nights'.
"The group was disappointed against Catalans and it looked like we hadn't played for three weeks, which we hadn't. I'm not using it as an excuse but it played a part, it felt like a friendly game.
"I'm happy that the fans are back, we've missed them but there wasn't much to cheer about, so I apologise for that."
Oliver Gildart marked his return to the side for his first game this year with two quickfire tries in the second half to cut the margin to four points and offer brief hope of a fightback. But Adam Quinlan's try with five minutes to go secured Hull KR their first victory at Wigan since 2009.
"You could see that Gilly and Liam need some game-time, there was a bit of roughness, but it was good to get them back," added Lam.
Having won their first seven matches of the Super League campaign, Wigan have now posted successive losses - they were also hammered 48-0 at Catalans - ahead of next Thursday's trip to Wakefield.
Robins coach Tony Smith said: "We showed some real character, I'm not sure how many sides come here and keep Wigan to nil by half-time. I think at one stage we went 23 tackles straight on our line, which takes some character.
"I thought we contributed to our own - not demise - but workload, with our handling errors out of our own end. But the character was outstanding, it repelled most of their attack.
"I thought we looked like the better team for most of the game."
Asked why George King was sinbinned late in the first-half, Smith added: "That's not a question I can answer."