Paris: Serena Williams has emerged as an unlikely ally in Bernard Tomic's stunning journey back from the tennis wilderness to the grand slam stage.

Serena Williams has been traingin with Bernard Tomic at her French base. Credit:AP

Williams' esteemed coach Patrick Mouratoglou was a vocal courtside supporter as Tomic sealed his place in the French Open main draw with a gritty 7-6 (7-5), 7-5 final-round qualifying win over Portugal's Goncalo Oliveira.

Mouratoglou later revealed Australia's fallen star had been training with Williams at his French academy, located 45 minutes from Tomic's Monte Carlo base, and was considering a permanent move as he fights to resurrect his once flourishing career.

"He practiced with Serena actually," Mouratoglou said ahead of Tomic's first-round showdown with countryman Nick Kyrgios.