World number one Tiger Woods finally broke through the 70 barrier on Saturday with an impressive eight-under-par 65 that vaulted him up the leaderboard at the Mercedes Championships.

Woods is in fifth place at 13-under-par, seven shots behind leader Stuart Appleby.

Surprised by his inconsistent play after just three weeks off from competitive golf, Woods finally got off to a strong opening to his round with three straight birdies.

In the previous two rounds, he was four-over-par on the opening two holes.

"A good start is the only way you can shoot 10 or 11-under-par here, only way," Woods said.

"You need to be two, three, four-under-par by the time you get to the par five, because you can really feel that you can get it going."

The world number one's round was the second lowest of the day, topped only by playing partner Retief Goosen, who went one better with a nine-under 64.

Woods admits to leaving some shots on the course, a common theme for the player early in the season.

"I felt like I've been playing well but keep making silly mistakes on the first couple of days," he said.

"Today I three-putted twice and made par on the sixth when my three wood rolled right off the green, so I should have, probably, realistically been either two or three shots better."

Woods has a difficult task ahead of him if he is to win his 40th PGA Tour event and third Mercedes Championships.

"I just need to get on a roll to have a chance, need to shoot a front nine like Goosen did today," Woods said.

"If I do that, I have a viable chance duplicating that on the back nine and at least posting a number."