Many believed that with such limited game time and such fierce competition for the back-row places, Lydiate could miss out on the tour altogether, but anyone close Gatland would have reckoned otherwise.
Lydiate was a key part of Wales' Grand Slam success in 2012, he had history of dovetailing with close friend Sam Warburton in the back row and, most importantly, he tackles trucks.
He was on the bench for the first Test and when he was then skipper for the night against Melbourne Rebels, some thought it was Gatland's way of softening the blow.
In he came to the side for the second Test however, making 13 tackles and four carries and it was in the third Test where he truly excelled.
In Sydney Lydiate made nine tackles, not missing one, throughout the tour he made a total of 57 - and one of them was absolutely crucial, hitting Benn Robinson hard with the Lions camped on their own line with 20 minutes to go, and in doing so forcing the turnover.
"Getting capped for Wales was a massive honour but to be part of a winning Lions tour is incredible," said Lydiate.
"To not only have played in the Tests but to have captained the Lions (against Melbourne Rebels) is a dream come true.
"It's still not really sunk in and I'm over the moon to have been part of this, especially after being injured for so much of the season (after breaking his ankle in September).
"I counted myself lucky to be on the tour so to get a cap off the bench was incredible then it got even better with two starts."
But perhaps it is others who sum up Lydiate best.
Jamie Roberts says of Lydiate: "He rarely misses a tackle and is a guy who hits very, very hard. You know when you have been on the receiving end of a Lydiate tackle."