Masters a mental rollercoaster for McIlroy

Winning the Masters is becoming a mental challenge for Rory McIlroy because it's the only major he lacks for the career grand slam.

The biggest hurdle might be the third round.

For the third time in five years, McIlroy went into the weekend within range of the lead, only to blowup on Saturday. He was one shot behind in 2012 and shot 77. He was four shots behind Jason Dufner in 2013 and shot 79.