NASCAR In-Season Challenge starts Sunday at Sonoma Raceway

The highest finisher in each pairing advances through the five-race bracket, and the overall winner receives $1 million. Two drivers who met in last year’s first round sat for a joint interview Saturday at the track. Both appeared in black attire and answered questions without trading barbs, leaving any competitive comments to their daughters who have become friends at the track.

First-round matchups and format The bracket begins at Sonoma, the last road course on the Cup schedule. Additional rounds are scheduled at Chicagoland Speedway, North Wilkesboro Speedway, and Indianapolis Motor Speedway. One driver ranked 31st this season enters the event after reaching the final last year as the 32nd seed.

That driver has recorded a best finish of 12th in 2025 but has not won a Cup race or reached the playoffs in more than a decade of starts.

Additional first-round pairings Other first-round pairings include two former teammates from the same organization and a matchup between drivers who previously shared a team. A driver seeking a new ride after this season is also paired in the opening round.

A driver making a 500th Cup start at the track nearest his hometown is entered in the event. That driver has not recorded a top-five finish in 15 prior Sonoma starts. The defending race winner enters as the betting favorite for Sunday’s event.