Tiger Woods had to sit and watch longtime rival Phil Mickelson become the oldest player to win a major championship. He is also enduring a grueling rehab following injuries suffered in a single-vehicle crash earlier this spring.

Woods spoke to Golf Digest about his rehab process as he recovers from multiple leg injuries suffered in the crash, calling it the hardest thing he has endured physically:

“This has been an entirely different animal,” Tiger Woods said, via Daniel Rapaport of Golf Digest. “I understand more of the rehab processes because of my past injuries, but this was more painful than anything I have ever experienced.”

Tiger Woods' mental makeup has helped him dominate the sport of golf since the late-1990s. But the 15-time major champion understands he has a long road ahead.

In fact, Woods was not willing to comment on whether he hoped to return to the course:

“My physical therapy has been keeping me busy,” Tiger Woods said, via Rapaport. “I do my routines every day and am focused on my No. 1 goal right now: walking on my own. Taking it one step at a time.”

Aside from the painful road back, Woods also had to observe Mickelson make golf history as “Lefty” received a tremendous ovation from the crowd at Kiawah Island this past weekend.

On the one hand, Woods was one of the first to send his congratulations to Mickelson. He called Mickelson's win “inspirational.”

Still, as competitive as Tiger Woods is, it would not be a surprise if Mickelson's triumph eats at him a little bit. Or, perhaps it will motivate him to get back to the grind.

Regardless, Woods seems to understand this rehab process is a different animal.