But from the moment Owen Glenn and Eric Watson stood on a stage at SkyCity on that Thursday last month and told everyone how wonderful the club was about to become, McClennan's mistakes became magnified.
Watson offhandedly assured those in attendance that Bluey and the boys would crush the Knights the following Saturday. Watson might have checked the form guide. The Knights were running hot, the Warriors not so much.
"Before the Newcastle game we had the big announcement about what's going forward at the club, and we were up 18-0 and let that one go," McClennan said. "A bit of pressure went on from there and we just didn't come up with the results, so I can understand the club's perspective.
"They're very determined to get results and so was I but I haven't done good enough on this occasion."
The reality for McClennan is that "this occasion" is almost certainly his last shot as a professional club coach. No NRL club will touch him now, and while doors may open in England, he is reluctant to relocate his family.
While he was understandably "gutted" at having his dream job ripped away, he was not surprised when the axe finally fell on Monday night.
The writing had been on the wall for several weeks. On Friday the Herald reported that McClennan would be sacked if the team suffered a bad defeat to the lowly Panthers. That story was met with disbelief in some sections of the media. Tellingly, its accuracy was never denied by the club.
The two-point margin of Sunday's defeat was not terrible, but the match itself was. In the end the scoreline mattered little.
As he looked around the swathe of empty seats at Mt Smart Stadium, McClennan would have known the game was up. The club had pre-sold about 13,500 tickets. The announced attendance was slightly more than 11,000, but may well have been lower.
The fans had spoken with their feet, and there was no way an ownership with designs on becoming the Southern Hemisphere's premiere sporting franchise would ignore that level of dissent.
The owners have sent a message to the fan base that failure is not an option, that they are prepared to act decisively. The next major statement will be the identity of the new coach.
That could be bad news for stand-in Tony Iro. The talented club stalwart has served his apprenticeship and is widely respected. He has two games to show he is the man for the job, but regardless of how those matches against the Dragons and Raiders pan out, the appointment of another rookie head coach will be a tough sell. The same can be said of Stephen Kearney after his failure at Parramatta.
If McClennan's ruthless axing is any indication, a big name recruit should be expected.
The search has already begun. McClennan is yesterday's man. He departed with dignity. His sole protest regarded a headline on the Herald website that suggested he had simply had enough and quit.
"Mate, I ain't no quitter," a text message to the paper said.
