And now Gatland, who also toured the Republic with the Lions as forwards coach, has paid Jenkins the ultimate compliment.
"I think Gethin is the best loose-head in the world," said Gatland when naming his 29-man squad for the four November internationals.
Injuries to the likes of John Yapp, Iestyn Thomas and Jenkins' fellow Lion Adam Jones have left Gatland short of front row options for the upcoming series and the New Zealander admits he may have to switch his prize asset to the other side of the scrum as a result of the withdrawals.
But while some props would baulk at the prospect of moving from loose head to tight-head at such short notice, Gatland insists Jenkins has no such worries.
"We've got to back ourselves that we can get our scrum operating against a very good All Blacks scrum," said Gatland.
"Both Gethin Jenkins and Paul James are in consideration as props who can play on both sides of the scrum.
"It's a decision we need to make whether you move the best loose-head in the world to cover you at tight-head.
"The great thing about Gethin is that he has no fear about putting that No 3 jersey on. He says 'just give me the jersey and I'll do the job'.
"So that's the sort of attitude he has as a player and whether it's at one or three he'll do a great job."