Peter Piston will announce power ratings every week of the NASCAR season. Check out this week’s edition of NASCAR power ratings below, and listen to SiriusXM NASCAR Radio (Channel 90) on the SXM app now. Check back for previous editions of our Power Rankings here. 
The NASCAR Cup Series round of 16 came to an end Sunday at Martinsville Speedway. Here’s a look at the power ratings after Xfinity 500:
1. Ross Chastain
An insane move to run wide open against the wall in turns three and four will put Chastain on the NASCAR highlight reel as long as there’s NASCAR. The spectacular move was also instrumental in getting Chastain to Championship 4 as the storybook season for Trackhouse Racing progresses.
Playoff grid: 3rd
Last week: 1st
2. Christopher Bell
For the second time in this year’s playoffs, Bell found himself in a situation where he had to win to stay alive. He did it at The Roval to reach the Round of 16 and then did it again on Sunday at Martinsville. His third win of the year puts him in Championship 4 with a chance to win his first career Cup Series crown.
Playoff grid: 2nd
Last week: 9
3.Joey Logano
Don’t worry about Logano heading to Martinsville with his Championship 4 spot already secured thanks to his win in Las Vegas to open the round. Logano didn’t lead any laps, but came out of the race with a decent sixth place finish.
Playoff grid: 1st
Last week: 4th
4. Kyle Larson
Admittedly, Martinsville isn’t one of Larson’s best tracks, but he let him rest over the weekend by winning the pole, leading 68 laps and finishing second in the Xfinity 500. Larson has a win and a second in the last two weeks as he finishes the season strong.
Playoff grid: 7th
Last week: 3
5. Chase Elliott
A very average Round 8 for Elliott ended with a top 10 finish at Martinsville on a day in which Elliott led the field for 54 laps and was mostly at the front of the running order for the day. It wasn’t spectacular, but it was good enough for Elliott to have a shot at championship number two in the Cup Series at Phoenix.
Playoff grid: 4th
Last week: 5
6. Denny Hamlin
For the fourth straight year, Hamlin will miss the Championship 4. He led a race-high 203 laps at Martinsville on Sunday and added a pair of stage wins to his resume. It all came down to execution, though, and Hamlin’s team came within a whisker of earning a spot to contend for the title on Sunday at Phoenix.
Playoff grid: 5th
Last week: 2
7. Ryan Blaney
Time has finally run out for Blaney in his quest for a championship. There was speed in the No. 12 Team Penske Ford, but even a third-place finish wasn’t enough to keep Blaney’s title hopes alive and he was eliminated from the playoffs when he waved the checkered flag.
Playoff grid: 8th
Last week: 8
8. Pursuit Briscoe
A bold pit strategy to not whistle for tires gave Briscoe the lead at the end as he tried to maintain his Cinderella story in the Playoffs. That was not to be, however, as a caution flag late derailed that strategy and the Stewart-Haas Racing driver finished ninth at Martinsville.
Playoff grid: 10
Last week: 10
9. William Byron
A little speed early on kept Byron in the hunt for a Championship 4 playoff spot. But despite his seventh-place finish, a top-10 performance at Martinsville wasn’t enough to get the Hendrick Motorsports driver into the title race.
Playoff grid: 6th
Last week: 7
10.Tyler Reddick
He left the race early complaining that he just didn’t feel right in the race car. Hopefully it’s nothing serious, but Reddick’s day ended after just 188 laps with damage to the front end of his Richard Childress Racing Chevrolet and a 35th-place finish.
Playoff grid: 13
Last week: 6
Abandoned: None