The Houston Rockets and San Antonio Spurs both had a tough time getting out of their respective series. The games were close, but ultimately they pulled through. Here are four key players you need to watch in their second round matchup.

Kawhi Leonard

Kawhi Leonard has been arguably the best player in the playoffs thus far. When times were getting tough for San Antonio, Kawhi was hitting everything he shot. Kawhi is averaging 31 points per game on 54 percent shooting and 48 percent shooting from three. Not only that, he's getting to the free throw line 10 times a game.

Kawhi has been unstoppable, and this series against Houston doesn't look like it will be any different. Houston doesn't have anyone able to guard Kawhi, so if San Antonio wants to take this series, it will feed straight through Leonard.

James Harden

James Harden had one great season and a decent first round. Harden posted a 33/7/6 stat line and didn't shoot the ball that well. He thrived off getting to the free throw line and taking shots at the rim. Harden is a difference maker, and the biggest thing to watch in this series is how Kawhi Leonard defends him. The first thing to look for is if Kawhi will go over or under the screens and if the Spurs will try to switch them. Harden has been a master all season at reading the pick and roll, and it's one battle he'll have against Kawhi.

Ryan Anderson

Ryan Anderson is a huge key for the Rockets. Against the Spurs, he'll be a fairly large defensive liability against guys like LaMarcus Aldridge. The big key for Ryan Anderson and what to watch for is how aggressive he is and how consistent he is on offense. Anderson did not shoot the ball well against the Thunder, shooting an atrocious 12 percent from three.

No one is sure why the sudden massive drop in numbers from Anderson but when he hits shots their offense is so much more fluid.

Patty Mills

Patty Mills is an X-factor in this series. The Houston bench is very, very good but Patty Mills can take on any matchup off the bench and go straight into attack mode. Mills will be guarding Lou Williams and Eric Gordon a lot, and this matchup will be huge.

Whichever player can contribute more on the offensive end will be a real deciding factor in which team wins this series. He'll need to be spot on for the Spurs to hang on The Rockets' bench.

These four players all contribute to their team in different ways. They will be very valuable in this series for whichever team pulls out the win.