He used to sneak onto this course as a youngster, taking a few wedge shots before members came into view. "A lot of times the adrenaline of a tournament can get you through", he said. He beat FedExCup leader Dustin Johnson in Abu Dhabi in January, then finished second to Johnson at the World Golf Championships-Mexico Championship.
The 28-year-old told Press Association Sport: "Look, I'd still like to be up in Scotland playing, of course, but if it gives me a couple of extra days to learn this golf course then I don't really mind".
He said: "To get the win in 2014 and get my name on the Claret Jug was a huge step in my career, and a huge step in me feeling a complete player".
"In 1998 I remember Tiger Woods walking past me".
Ian Poulter, who teed off almost an hour before Harrington on Sunday, quickly set the new mark with a closing 69, one of just six under-par cards on Day 4 and a round that included the most Poulter-esque of finishes.
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Manifesti e striscioni sui balconi di Bagheria per ricordare il magistrato ucciso dalla mafia nella strage di via d'Amelio. .
Harrington, playing in the early wave, started his title defense with a bogey at his first hole and closed his round with back-to-back bogeys for a 4-over 74, which normally would be a reason to start planning for a short week.
"That one hit me hard", he said. In 2011, at age 20, he became the youngest player to win the money list on the Challenge Tour (Europe's version of the Web.com Tour). He has two wins this year and has yet to miss a cut in 2017. But his game started to slip, and by last September he was down to 188th in the world ranking.
US Open champion Brooks Koepka will be looking for back-to-back major successes and will start his quest alongside world number two Hideki Matsuyama and home hopeful Tommy Fleetwood. "I just didn't know anything that would happen".
Just six players managed rounds at or under par on Day 1 in '08 - with Robert Allenby, Graeme McDowell and Rocco Mediate leading the way with 69s - and the scoring average on Thursday was 75.87. I don't feel I have enough game to play the way I want to, and as soon as you go into practice mode you are losing the possibility to play your best. "I felt fine. And I felt comfortable".
He'll have plenty of eyes on him again this week.
You can see the tee-off times and pairings for the first two days of the Open Championship here.