It is the NBA playoff series everyone has been waiting for.

The Western Conference semi-final matchup between reigning champions the Golden State Warriors and Houston Rockets promises to be one of the best of the postseason.

Both teams are considered contenders to take home the championship and feature star players throughout their line-ups.

Golden State and Houston met in the Western Conference finals last season. The Rockets held a 3-2 lead before Chris Paul suffered a hamstring injury and missed the rest of the series. The Warriors won the final two games and went on to capture their second straight championship.

"Well, I thought we had a great crack last year, so I don't know — we'll see," Rockets head coach Mike D'Antoni told The Athletic last month. "I'm confident, as I was when we were 11-14, that we'll give them a run. … Now they might beat us. They're the best team. They're the champs right now. They've proven it, and they've got nothing to prove."

Here are three things that could decide the series this time around:

Capela's ability to stay on the floor

Clint Capela can be a game changer for the Rockets.

The 6-10 center is a strong rebounder and finisher around the basket. He can also protect the rim, as he averaged 1.5 blocks this season.

The Warriors do not have any true center who could match up with Capela. However, they can counter with their "death line-up", which features Draymond Green at the pivot. That group can switch at almost every position and plays fast.

The small line-up could give Capela problems, which could force him to the bench if the Rockets decide to answer with one of their own.

But, if Capela finds a way to stay on the floor and keep up with Green, he has a chance to be a difference maker for Houston.

Warriors' fatigue level

The Rockets easily took care of the Utah Jazz in five games in their opening series. The Warriors, on the other hand, surprisingly struggled at times against the Los Angeles Clippers before eventually moving on to round two.

That means Houston have had extra time to rest, recover and prepare to face the two-time defending champions, while Golden State have had to expend more energy than they are accustomed to in the first round.

The Warriors have the more talented roster, but there is a chance fatigue could slow them down and play a role in this series.

Rockets' role players

The players surrounding Rockets stars James Harden, Paul and Capela have changed since the last time these teams met in the playoffs.

Houston have added guard Austin Rivers, wing Danuel House Jr. and forward Kenneth Faried since last season. They will need those role players, along with PJ Tucker and Eric Gordon, to contribute on both ends of the floor if the Rockets want to win the series.

The Warriors have multiple dynamic stars, which makes them difficult to match up with. But, the Rockets should have the versatility to slow them down.