The former world number one had birdied his last four holes in the opening round and was soon making further progress when he holed from 25 feet on the third, but dropped his first shot of the week on the seventh after driving into a fairway bunker.

A birdie on the ninth took the 29-year-old out in 35 and three more birdies and one bogey on the back nine meant Kaymer - who secured the point to ensure Europe retained the Ryder Cup in 2012 - set a testing target for the later starters.

Kaymer, who won the US PGA Championship in August 2010 and became world number one the following February for eight weeks, said: "It was very difficult today.

"It was a little tougher especially when you shoot such a low score, your expectations are very high and you need to find a way to lower those expectations and see it as a new day so 69 was a very good score today. The pins were in some corners and it was more windy so I am very pleased.

"I didn't hit as many fairways as yesterday, but I managed my way quite nicely around the golf course, had a couple of nice up and downs and two longer putts went in. I think I kept it really well together and kept myself in the tournament.

"It's a great start, but we are only halfway."

Kaymer's last win in a full-field event came in 2011 but the German has been moving in the right direction this season and added: "I've had a lot of good finishes.

"I was very happy the way I played golf the last four or five weeks, so the next step is just putting yourself in contention, hopefully win. If not, it's okay, but as long as you put yourself in contention for the next few weeks, especially now we're coming up to the US Open and British Open.

"It would be nice to gain even more confidence and if you sneak in a win here and there it would be nice. If not, it's still good golf and good performances."

Adam Scott was facing an anxious wait to see if his latest bid to become world number one remained alive, the Australian rebounding from his opening 77 - which featured double bogeys on the 17th and 18th - to return a 67 with three birdies in his last four holes.

Scott, who could have overtaken the absent defending champion Tiger Woods by staying at home, needed at least a top-16 finish but was level par for the tournament with the projected cut at one under.

"I don't think I played that much better than yesterday to be honest," the former Masters champion said. "Hopefully it will be good enough to play the next few days. If not it will be disappointing."

Henrik Stenson, Bubba Watson and Matt Kuchar were also able to overhaul Woods depending on their results, with Stenson needing a top-six finish, Watson to finish alone in second and Kuchar requiring a victory.

European number one Stenson and two-time Masters champion Watson were three-under, with Kuchar two under after a second consecutive 71.