Clarke earned an emotional victory at Royal St. George's in July, winning the major in his 20th attempt.
Since then, the 43-year-old Northern Irishman has missed the cut twice, finished tied for 68th at the Bridgestone Invitational and tied for 35th at the European Masters.
Clarke said Wednesday that being appointed Ryder Cup captain is the biggest challenge left in his career.
First up, however, is the Dunhill Links Championship this week. He'll be playing in a field with U.S. Open champion Rory McIlroy and Masters champion Charl Schwartzel with Ryder Cup points on the line.
Clarke said he's been taking motivational advice from those closest to him.
"I've done what I always wanted to do, got to the top of the mountain — what else can compare to it?" Clarke said. "What else is there to do?"
It's made Clarke appreciate just how hard it is for athletes, particularly those who have achieved success late in their careers, to keep on going.
"I've no idea how Steve Redgrave did it," said Clarke, referring to the British rower who won five Olympic golds — the last coming in 2000 at 38. "It's not as if I'm 21 or 22. I'm 43. Whether I get another chance to win a major, it may not happen."
After playing five Ryder Cups — including four victories — one of the few challenges left for Clarke is to one day captain the European team.
"In terms of my golfing career, I've won World Golf Championships, I've won the Open, I've won tournaments all around the world — I've had a pretty decent career," he said. "At some stage in the future, I might be asked to be Ryder Cup captain. What more could I do?"
Plenty of Ryder Cup points for next year's match in Medinah, near Chicago, are available from the Dunhill Links Championship. Clarke plans to take seriously, yet enjoy, the pro-am tournament in Scotland.
"It's a huge tournament for us on the European Tour. First prize is a lot of Ryder Cup and world ranking points. We will be laughing and joking and we'll all be trying to play well," said Clarke, who will be partnered around St. Andrews, Carnoustie and Kingsbarns by his manager Chubby Chandler.