The Kiwi is heading into his third season with same driver pairing and feels the three of them - Hartley, Webber and Bernhard - are well suited to race together and have gelled really well. The Herald caught up with the 26-year-old New Zealander on the eve of the opening round of the 2016 season to gauge how he and the team are feeling as defending champions.
"We've a had lot of testing and a full preparation week in the run up to this weekend running through every possible variation.
"We're really prepared and ready to go racing. We have to be a little wary of our competitors as they have completely new cars, whereas we got new bits but they have new technology as well.
"We'll be a bit disappointed if we don't do well at Silverstone as we gained a lot of confidence last year [winning the title]. Having the number one plate on the car does make you a bit of a target though, but everyone's looking forward to the challenge."
What will help Hartley and the team is that they are in known and proven car, have the same line up of drivers and have a bunch of engineers and mechanics who know the car inside out. The WEC is not an easy championship to win and on the plus side the trio in the number one 919 know they can win and will be hoping to continue where they left off last season.
"We haven't backed off, nor has anyone else in the team, from last year and we'll be going just as hard as ever. Silverstone is a track I like, and Mark [Webber] has had a lot of success here as well.
"Last year we took pole and Mark was leading until we had a mechanical issue, and we looking forward to making a better start to the season than last year [no points from Silverstone and very few at Spa]."