By Michael Vega, Globe Staff

NORTON --- Luke Donald, ranked No. 2 in the world's golf rankings, apologized after his round Sunday at the Deutsche Bank Championship at TPC Boston for remarks he posted Saturday on his Twitter account that were critical of the course's revamped 18th hole and its designer, Gil Hanse.

After he bogeyed the 530-yard par 5 18th, Donald expressed his frustration when he tweeted: "Nothing quite like hitting my best shot of the day into the last and walking off with a bogie, what a terribly re-designed green #sourtaste"

Later, Donald mistakenly tweeted his cell phone number and a remark that was personally critical of Hanse. He meant them to be delivered as a private direct message, but instead he caused a minor controversy when it went out to Donald's 300,000 Twitter followers.

Both wound up being quickly deleted.

"I made a mistake," Donald said after he shot a 70 Sunday to remain 15 shots off Louis Oosthuizen's lead (19-under). "Unfortunately, I made an error. I sent a message out on Twitter that was not meant to go out on Twitter and I take full responsibility. I realized it immediately, tried to delete it and tried to move on. Unfortunately it got caught up there, and such is life. I didn't mean to put it out there and I apologize to anyone I offended, especially Gil Hanse."

Donald, however, remained steadfast in his critical opinion of the 18th hole.

"I'm still not that keen on it," he said. "I think the Tour has done a great job in terms of making this course a lot better. I just think some of the design in that hole is a little severe. Obviously I was pretty heated, and certainly by the time that message went out, I had calmed down a lot, but it certainly wasn't meant to be public."

Donald was forced to shut off his cell phone after he was inundated with so many calls. ``Probably a new number is in store for me -- that's what I deserve,'' he said.

Donald also expected to be a little more cautious in his use of social media, such as Twitter, in the future.

"Well, it's certainly a powerful tool, and you've got to be very aware of it," Donald said. "There's a certain addiction to Twitter. It's that constant update that everyone enjoys. But probably wise if I took a little bit of a hiatus maybe."

in other noteworthy items from the third round of the Deutsche Bank Championship:

* Louis Oosthuizen shot a blistering 8-under 63 to go to 19-under, good for a three-shot lead over second-round leader Rory McIlroy (16-under). Oosthuizen set tournament records for his outward nine-hole score of 29, for the seven consecutive birdies he made on holes 4 through 10, and for the lowest 54-hole score (19-under 194).

"Obviously probably the start anyone would dream of on that front nine,'' said Oosthuizen. "I made everything, so you get those days where you just look at the putt and you hole it. That was my first nine holes.''

* Oosthuizen wasn't first in the clubhouse with the low round of the day. That distinction belonged to Keegan Bradley, who shot an 8-under 63 as well. He was thrilled to make the cut after shooting a 2-over 73 Saturday in the second round, representing a 10-shot swing between second and third rounds.

Bradley, who started off his round with an eagle on the par 5 second hole, was 9-under for the round after he birdied 16. He went to the 17th tee one shot off the course record set by Vijay Singh in 2006 and later matched by Mike Weir in 2008. He wound up making bogey and dumping his approach into a greenside bunker on the 17th.

He salvaged par on the 18th after his 204-yard approach shot ricocheted off a rock in the hazard and went dead right out of bounds into the woods along the right side of the fairway. He dropped and stuffed his fourth shot to within 4 feet of the pin.

"I spoke to my mom and my mom told me my grandmother wanted me to shoot a 63 today,'' Bradley said. "So I was out there thinking I had a good chance to do that for her. This is her first tournament she's ever come to, so I needed to get up-and-down to make that putt to shoot 63.''