MORE: Full race results " Series standings
RELATED: Full coverage of the Chase for the NASCAR Sprint Cup format changes " Official news release " Changes explained " Chase Facts and FAQ " Chase Grid (PDF)
Stewart-Haas Racing has now won two of the first six Sprint Cup Series races of the season, including Kevin Harvick's victory at Phoenix.
Busch, 35, won for the 25th time in his Sprint Cup career and ended an 83-race winless streak.
Dale Earnhardt Jr. regained the points lead after placing third on Sunday. Earnhardt Jr. now has four top-five finishes this season, including his win in the season opener at Daytona.
Kyle Busch moved up a spot to sixth after placing 14th on Sunday, and Brad Keselowski, who won the race at Las Vegas, dropped three spots to seventh in the standings with his 38th-place finish at Martinsville.
If Kurt Busch, Kyle Busch, Edwards, Keselowski, Harvick or Earnhardt Jr. win at least one more time this season, they would be guaranteed a spot in the Chase for the NASCAR Sprint Cup.
Drivers with one win through the first 26 races must rank among the top 30 in the points standings to qualify for the Chase.
After the sixth race of NASCAR's regular season, here is how the Chase for the NASCAR Sprint Cup standings look:
|1.||Dale Earnhardt Jr.||Winner: Daytona|
||Winner: Las Vegas
||2nd in points|
||4th in points|
||5th in points|
||8th in points|
||9th in points|
||10th in points|
||11th in points|
||12th in points|
||13th in points|
|16.||Marcos Ambrose||14th in points|
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