Former Roma midfielder Radja Nainggolan nearly spoiled Beveren's party after assisting Patro Eisden team-mate Japhet Muanza's 1-0, but the visitors bounced back after Kurt Abrahams levelled the score before half-time and two own goals from Stef Peeters led SK Beveren to a promotion-clinching 4-1 win in Maasmechelen.
The American-owned club are now on 66 points and remain unbeaten after 24 rounds. With only eight rounds to go for Beveren, and seven for chasers Lommel and Beerschot, the Waasland outfit cannot fall out of the top two places anymore.
The promotion is the earliest in the history of the Challenger Pro League. Beveren, who have won their last 10 league games in a row, are now chasing the coveted record set by Royale Union Saint-Gilloise in 1934, when the team from Brussels went invincible.