Are you ready for the toughest test in the MLS west? The Colorado Rapids are one of the 2016 season’s Cinderella stories, going from worst in the Western Conference last year, to neck-and-neck for first this one.

And the team with whom they’ve been fighting for that number-one slot in the standings? FC Dallas, who meet them in Commerce City on Saturday (9 pm ET; MLS LIVE). They just barely missed last year’s Supporters’ Shield, and no doubt they're gunning hard for it again this year. In other words, neither of the league’s top Western contenders are going down without a tooth-and-nail fight.

Here are three reasons why this game is essential viewing:

1. THE RAPIDS’ REMARKABLE RUN: It’s going to take everything to topple Colorado on their home grounds, Dick’s Sporting Goods Park. After a July 16 home win over Sporting Kansas City, they’re currently enjoying an unbeaten run in MLS play of 14 matches, 10 of those at home.

2. CASTILLO’S COMEBACK TEAR: For a minute there, one might have been worried about FC Dallas’ Fabian Castillo, when it seemed the standout Colombian had hit a lull, with just three assists and three goals in 17 games this season. Well, that’s over. This past MLS weekend, he served up this jaw-dropping rabona to assist in a Maxi Urruti goal—only to later assist on another goal, the team’s third, finished by Mauro Diaz. Anyone on the wrong side of seeing him barrel down the flank should be very, very scared.

3. IT AIN’T OVER UNTIL...: Nobody can rest easy early on—both of these teams excel at some late-game theatrics. Case in point: The Rapids’ last home game on July 16, vs. Sporting Kansas City. Things stayed tied 0-0 all the way up to the 78th minute, when Colorado’s Marlon Hairston finished a Dillon Powers pass.

And Dallas, for their part, kept the scoring going into stoppage time vs. the Chicago Fire on the same night. However things are going, you’ll want to stay tuned until the clock winds completely down.