Jordan Spieth on new driver to open Masters: It worked out

— -- AUGUSTA, Ga. -- A 6-under-par 66 suggests it wasn't a big deal, but Jordan Spieth nonetheless found himself scrambling on the eve of his Masters defense after discovering he had cracked the face on his driver.

Spieth sensed something was wrong because his ball flight was off when he hit shots on the driving range Wednesday.

His coach, Cameron McCormick, inspected the driver, and sure enough, he noticed something was amiss.

"He grabbed the face to see if I was hitting it lower or higher on the face to produce that, and he said, 'We've got a problem,''' Spieth said. "And it was the same crack actually the last three drivers, when I decided to change, all with the same crack.

"It's just a little horizontal line at the middle, kind of right where you want to hit the driver, middle to top of the face. And I had one in college, and then I had one the day before the 2014 Players and I went to my backup.''

Spieth said he took the shaft off the affected club and then experimented with four different driver heads. Spieth plays with a Titleist 915D2 9.5-degree driver. It is common for the equipment companies to be on site, and Spieth was able to do some testing at Augusta National -- although it was late in the day.

"We mixed around a little bit the swing weights,'' he said. "I hit probably five or six balls with the four heads and chose what I thought was the best.

"Obviously not ideal ,but I hit balls obviously this morning before the round, and everything seemed fine. It worked out in today's round. I did hit a lot of 3-woods today, but my driver didn't cost me anything.''

For the day, Spieth hit just 8 of 14 fairways and 12 of 18 greens. But he made six birdies, no bogeys and took just 25 putts in his round of 66. He leads Danny Lee and Shane Lowry by two strokes entering the second round Friday.