Umaga, the 42-year-old former All Blacks captain who played 74 tests, admits these next few weeks - early in the new year with the players training in the heat at their new base - could be the happiest of 2016 for the Blues.
The air is alive with optimism without the blemish of defeat or travel-weariness in a new expanded competition likely to be met with initial incomprehension by many supporters of Super Rugby. There are no injury problems or form issues and no losses to explain to expectant media and fans.
"Everything points to us going well," he says. "Training's going well, our environment is positive, but we haven't played a game. We're 100 per cent. We want to keep that feeling."
The scrutiny associated with the Blues has always been high. The franchise had a glorious start to the competition in 1996, winning the first two titles and adding a third in 2003, but haven't claimed it since, despite a huge advantage over the rest of New Zealand in terms of Auckland's population base.
Since 2003, of the Kiwi teams, the Crusaders have won the competition three times and the Chiefs twice. Last year, against the odds, the Highlanders won their first title.
For the Blues, there were semifinal losses in 2007 and 2011, but after the franchise's bright beginnings, it has become synonymous with inconsistency and failure.
Umaga is the latest in the hot seat and is, he says, ready for the pressure and expectation.
"I came into this with my eyes wide open. We've been an under-performing club for a while now. We make up the vast majority of our country's population and there is huge expectation on our rugby here in this region and especially this city.
"On the other side of that, I've lived with expectation for most of my life. I think I've got good things in place to help me with that, but ... I also have huge expectations of myself and those around me. For me, those expectations out-weigh anything from the outside."
A fit-looking Umaga, a Hurricanes favourite who was still playing in 2011 for the Chiefs following his time playing and coaching in Toulon, was direct on the field and is straight to the point off it.
There were questions about whether Kirwan, for all his personality and charisma, could get the point across to his players, but that is unlikely to apply to his successor, who has already shown his ruthless side.
Last month's announcement that the Blues were dispensing with the services of first-five Dan Bowden, who has since signed with Bath, would have sent a message to Umaga's players that he is prepared to make tough decisions, and quickly.
Umaga, a father of four children with wife Rochelle who all live at the family home "five minutes" from the Blues' base, is attempting to mould a squad in his own likeness - mentally and physically tough, as well as self-sufficient - and that means setting strict guidelines.
"If we allow things to slip early, that's going to set the standard," he says. "Coaching is similar to parenting. You've got to set guidelines. Young players and young men are always testing boundaries, but if you set guidelines early and stay true to them then ... there has to be accountability.
Is he ruthless?
"I think I have to be in certain circumstances," he says. "I'm head coach ... in the end, it's my head that rolls if things don't go well. I've learned what works for me and sometimes I've got to make those big calls. There will be other big calls I have to make, too. It's just my job."
He says his coaching team of Glenn Moore and Nick White - both of whom also worked under Kirwan - and newcomers Paul Feeney and Alistair Rogers - are gelling well at their new purpose-built base which has presented a welcome change from their former, run-down, headquarters at Mt Albert's Unitec.
The signs are positive, he says.
"There are no excuses now. We've got the facility, we've got the resources, so hopefully it should lead to better performances on the field.
"I don't know if it wipes the slate clean, you can't do that, history will always be with us.
"What it does do is give us a launching pad for the 2016 season," he says.
Umaga's first big test with the Blues is against the defending champion Highlanders at Eden Park on February 26. The southerners' deeds in winning last year's title are an inspiration for Umaga.
"No one predicted what they were going to achieve last year. But what you could sense was they could pull everything together as a group. Every ounce of ability they had, they put it there because they were so committed to the cause. That's what we've got to grow as well."
