It's the first time a coach has won a title after winning it as a player - with his assistant Leon MacDonald similarly successful - and it allowed Robertson to perform what is now a trademark breakdancing celebration on the middle of the pitch. Afterwards he hugged a bewildered photographer.
"The 'hoo hey Razor Ray' song tends to come out at the end of these campaigns," Robertson told New Zealand media afterwards. "I'll more happily do it when we have situations like that. The boys start singing and you start to get a tingle in the old toes and off you go. It's a great way to finish the campaign."
For Lions coach Johan Ackermann, off to Gloucester, there was no such joy. But he and his players should extremely proud to have been so competitive in a match which could have got away from them.
He appeared resigned to his team's fate in a halftime interview, but for Robertson, the man known as 'Razor' since his playing days, the victory could hardly have been sweeter.
"I'm just really, really pleased for the boys, for the team," he said. "They've worked so hard and got so close, the most consistent side in Super rugby history... it means we won't get questions from journalists at the start of every season like 'it's been a long time since you've won it, how important is it that you win this year?'.
"Those questions are gone, it plays on their minds. We've got a lot of All Blacks who have been successful on that front and now we've got All Blacks' Crusaders who have made their own history in a famous jersey."
Of the red card decision by referee Jaco Peyper, Robertson said: "Jaco was calm, he went through a process. The TMO confirmed that process... the right outcome came. Was it good for the final? No. Was it tough on the Lions? Yes. That's footy, Kwagga Smith's a great player and it's a shame it had to come to that, but the rules and the laws are as they are."
The Crusaders, scheduled to arrive home from Johannesburg late on Monday, got off to a brilliant start through Seta Tamanivalu and the impressive Jack Goodhue, but once Kieran Read scored after halftime they had to defend as never before. It proved to be enough.
"Defence wins championships and that won it for us tonight," Robertson said, before dancing off into the night.