Mickelson was able to tame the "Big Dog" in round one. Key to 66

Phil Mickelson put a new driver into play on Thursday at the Bridgestone Invitational and came away pleased with the results. No wonder — the 66 he shot propelled Lefty into a tie for second, two strokes behind Bubba Watson.

Mickelson’s instructor, Butch Harmon, actually suggested his student make the change to a shorter driver. So Mickelson asked the guys at Callaway to put an FT9 head on a shaft that’s only 44 inches and 20 grams heavier.

"I’ve only used it a couple of days, and it seems to be easier to hit, easier to swing," Mickelson said. "You’ll notice I don’t over swing with it. I’m not as long and loose with it. My timing is better.

"I always feel like when I make a swing similar to my irons or my long irons, my longer driver is always lagging behind, so you see me kind of hanging back trying to wait for it. And I didn’t feel that today. I didn’t feel that with the shorter one. I think it has some action to be in the bag for a while.

Mickelson said he didn’t think he lost too much distance off the tee — and indeed, he averaged 305.5 yards in the third roound. He hit 8 of 14 fairways, too.

"I seemed to hit the ball a little bit straighter with it," Mickelson said. "I’m obviously not going to hit it as far, but I thought the ball still came off pretty hot,and I wasn’t displeased with how far it was going. But it went a lot straighter.

"My misses when I missed the fairway was inside the tree line so I always had a shot into the green, and I thought that led to a lot more aggressive iron shots."

Even so, Mickelson didn’t off to the best of starts.

He teed off on the back and bogeyed Nos. 14 and 15 before getting back on track with a 6-foot birdie putt on the par-5 16th. Birdies at the second and third holes then got Lefty into red numbers but it was the lob shot he holed from 51 feet for birdie at No. 6 that may have turned an average round into a good one.

"I pulled an iron shot to the right, and I needed to get that up and down to maintain some momentum," Mickelson recalled. "I was only 1 under par, and I was just trying to keep it just a couple under, seeing if I could get one or two more. And when that lob shot went in the hole, it gave me a nice boost. Not only did I get it up and down but I made a nice birdie and was able to get two more coming in."

Mickelson’s playing partner, Rory McIlroy, was suitably impressed.

"He made a very mediocre round into a very good round, and that’s sort of what he does," said the young Northern Irishman who shot 68. "He can go on a run and make a few birdies. He sometimes makes them an unconventional way. He’s very good at just getting the ball around the golf course and shooting good scores.