Gael Monfils has had an eventful tennis career. He was once a top junior, winning three of the junior Grand Slams back in 2004. Since then, though, Monfils' injury-disrupted career has never quite panned out the way people expected.

For starters, no one can ever be sure exactly what style Monfils will bring to the court. He is one of the most powerful players on tour. He can consistently rip forehands well over 100 mph, and his backhand can approach the century mark as well. Some of the huge shots he hits leave fans exhaling, “Wow!”

But Monfils is also a defensive genius. His incredible athletic ability (more on that later) lets him run around behind the baseline and hit back everything deep for just about as long as he wants. Monfils is almost impossible to hit winners against, and he often keeps his defensive groundstrokes very deep in the court.

There are two things about Monfils that always seem to outweigh his tennis, though. His raw athleticism is unparalleled in tennis, and probably most other professional sports too. And his showmanship always makes him can't-miss entertainment. A basis to Monfils' defensive ability is that he can get to just about every shot that anyone can ever throw at him. And while it's the ridiculous gets and insane shots that make the highlight reels, it's the pure athletic ability to just hit defensive shot after defensive shot that really is the base of the Monfils game.

On the other hand, Monfils is often criticized for his propensity to showboat a bit. On the one hand, showboating in the course of the match is not always a bad thing. Roger Federer has been known to hit “tweeners” at times when they are not the best options. But Monfils' problem is that he does it too much, too often, and at the wrong times.

Since his amazing juniors career, Monfils has had trouble competing at the absolute highest of levels. He can shrink, at times, when the occasion gets too much for him. He does his best at his big tournaments near home, reaching the Roland Garros semifinal in 2009 and the Paris Masters final in 2009 and 2010. He has always had the talent to win Grand Slams, and he has always been able to beat just about anyone when he can stay mentally in the match. He has spent time ranked in the top 10 and won five titles in his career, all of them minor.

At this US Open, though, we have seen a new side to Monfils. He has been a showman at times, but he has been workmanlike throughout. He has not had bouts of bad play or stretches of inattention. He won his first 14 sets in this tournament, and it took strong play from Roger Federer just to take sets off him.

The fact is that this tournament was Monfils' sixth career Grand Slam quarterfinal. He looked better in this tournament than he did back in 2008, when he reached his lone Grand Slam semifinal. He didn't shrink here, even when Federer stepped up his game and took the match to him. Eventually he got tired and couldn't win the match, but he stayed focused and playing well for the entirety of the match, with one exception in the fifth set.. 

If Monfils can keep playing like this, and if he can stay healthy, there is absolutely nothing that can stop the Frenchman from going deep in Grand Slams consistently for the next three or four years, at least. His raw talent is stunning. And, if this tournament is indicative of anything, his attitude and mentality are finally catching up.