Tennis players are some of the fittest athletes in the world—and for good reason.

Players need to have a combination of speed, agility, power, strength, and quickness to track and return all types of shots—including blazing fast serves, backhands, forehands, drop shots, spin shots, and overhead slams.

Sometimes, just to make a return, they have to pull off the seemingly impossible—no-looks shots, behind-the-back shots, between-the legs-shots, around-the-net shots—and that sets up some amazing rallies.

Here's a look at some of the most astonishing shots in tennis of all time:

Roger Federer, Wimbledon 2015

While playing against Sam Querrey in the second round at the All England Club, Federer went royal with this too-cool-for-school shot between his legs:

Dustin Brown, Bergamo Challenger 2016

Brown—who shocked Rafael Nadal at Wimbledon in 2015—brought out the "wow factor" once again with this slick behind-the-back shot in Italy to get the point against Aldin Setkic, who had no chance for a return.

Serena Williams, Wimbledon 2010

Williams is a surgeon with her tennis racket—and at the All England Club against Vera Zvonareva, she showed exactly why with two powerful passing shots for winners. Zvonareva never had a chance.

John McEnroe, French Open 1984

McEnroe is legendary for his creativity with shots, and this drop shot on the clay at Roland Garros was one of his best. His opponent could only kick up dust in a futile effort to track it down.

Grigor Dimitrov, Stockholm Open 2014

Dimitrov gives fans a double feature in this match against Jack Sock. First, Dimitrov hit a fantastic behind-the-back shot for a winner, and then one-upped things with a between-the-legs shot for another point. Even Sock had to give Dimitrov some props with a fist-bump afterward.

Serena Williams, U.S. Open 2015

Bethanie Mattek-Sands had no chance against this furious shot from Williams, who went into a full split as she chased down the return.

Gael Monfils, Halle 2013

Monfils has shown an affinity for trick shots, and this one was possibly his best yet. The Frenchman let a shot from Tommy Haas drop in through his legs before spinning around and giving it a return. After a few strokes back and forth, Monfils won the point—and the adoration of the crowd.

Novak Djokovic, U.S. Open 2014

The Serbian star didn't even need the net. Djokovic took a wide shot from Diego Schwartzman at the U.S. Open and flipped it back around the net with a sliding forehand for the awesome winner.

Serena Williams, Australian Open 2015

During the 2015 final in Australia, Williams brought out a fantastic cross-court winner like it was routine, leaving Sharapova running the wrong direction with no chance for a return.

Maria Sharapova, Australian Open 2015

Serena Williams has dominated Sharapova during her career, but in the 2015 Aussie final, the Russian star got one over on Williams with an amazing drop shot that left Williams unbalanced and without an answer.

Roger Federer, U.S. Open 2009

The Federer–Djokovic rivalry has thrown off a lot of heat in the form of stunning shots and jaw-dropping moments over the years, but there's probably none better than this between-the-legs winner from the Swiss star. Djokovic couldn't help but smile at the return after losing the point.

Sam Groth, Busan Open Challenger 2012

There have been some blazing fast serves through the history of tennis—and most of those were put to shame with this serve from Sam Groth at the Busan Open, which was recorded at 163.7 mph.

Ivan Lendl, Nabisco Masters, 1988

Lendl and Boris Becker had some great matches against each other over the years, and this one offered up a fantastic finish with a match point winner from Lendl, who got some very timely help from the net.

Andy Murray, Australian Open 2010

There are wide shots, and then there are wide shots. Murray takes the return from Marin Cilic and splits the space between the net and the umpire's chair for the forehand winner. Even Murray’s mother was stunned, although she soon recovered and gave her son a round of applause.

Milos Raonic, Hopman Cup 2014

While partnered with Eugenie Bouchard during a mixed doubles match in Perth, Raonic pulled off the rare feat of winning a point while hitting the ball when it was on the other side of the net. After a high lob forehand from Bojana Bobusic, the ball bounced on Raonic's side of the net before bouncing back over, leaving Raonic to knock back the return. Somehow, he managed to stop himself from touching the net:

Agnieszka Radwanska, Sony Open 2013

Kirsten Flipkens hit a great return to Radwanska, who was tracking the ball perfectly—until it hit the net and completely changed direction. Using reflexes that are usually reserved for cats and superheroes, Radwanska maneuvered herself into a 360-degree spin and backhanded the shot over the net for the winner. Flipkens simply dropped her racket in awe and/or frustration.

Rafael Nadal, U.S. Open 2013

Ryan Harrison probably thought he had an easy point on the Spanish star after setting up a powerful overhand shot following a high lob—but Nadal had other ideas. After Harrison slamed the shot to the cross court, Nadal gave the return a quick flick of the wrist around the side of the net for a magnificent winner, momentarily silencing even the broadcasters.

Kim Clijsters, French Open 2011

The post got an assist on this one. After Clijsters flipped a return back and hit the net, it looked like the ball would go out of bounds, giving the point to her opponent. But the laws of physics were on Clijsters’ side this day—the ball bounced a second time on the net post and fell in for an unbelievable—and arguably lucky—winner.

Nick Kyrgios, Wimbledon 2014

Nadal had his hands full with Kyrgios at the All England Club in this match, as shown by this ridiculous between-the-legs winner. The Spanish star had little chance of mustering up a return—because Kyrgios barely looks like he even hit a shot back before winning the point.

Roger Federer, Madrid 2010

This isn’t basketball, but that doesn’t mean a head fake can’t work. Federer played that move to perfection against Ernest Gulbis on the ATP World Tour, coming in hard for a drop shot return and completely faking his head one way before putting the shot over in another direction for the clean winner.

Andy Roddick, Clay Court Shot

Roddick puts one into the clay—literally—with his serve.

Okay, this one was for a Powerade commercial. But can’t you imagine Roddick—who had one of the strongest serves in tennis history during his career—actually doing this?