ISMO athletes Jann Mardenborough and Katsumasa Chiyo have dominated the latest round of the Japanese Formula 3 by taking a win each at Fuji International Speedway.

Mardenborough was dominant in the lead up to race day, topping the times in both practice sessions and scoring pole for both races.

The former GT Academy winner was a massive 1.902 seconds faster than the chasing pack in qualifying in damp conditions for the first race. Mardenborough and Chiyo were 1-2 in both sessions.

Mardenborough scored his second win of the season in the opening race with Chiyo in fourth. In Sunday's race, the Japanese GT500 ace and former Bathurst 12-Hour winner Chiyo pounced on a late race restart to pass his teammate Mardenborough to score his first Formula 3 win of the season.

Chiyo also scored the fastest lap in both races.

Mardenborough now leads the championship by five points with seven races still remaining in the championship.