The McAms Yamaha rider streaked away after a brilliant start and never looked troubled as he saw off competition from Glenn Irwin (BeWiser Ducati) and Leon Haslam (JG Speedfit Kawasaki).
The second victory puts him right back into the title picture after an indifferent first half of the season.
He is now in fifth, right in amongst the battle for second spot in the standings ahead of the Showdown rounds.
Brookes, who began the weekend 130 points behind Leon Haslam at the top of the standings, snatched the lead from pole-sitter Irwin (BeWiser Ducati) early on, and never relinquished the lead for the full 20 laps.
Irwin finished second, with Haslam completing the podium, while Brookes’ team-mate Tarran Mackenzie agonisingly crashed out on the penultimate lap while in third.