ZUS Coffee pulled off a shocking 25-21, 25-23, 27-25 victory over the heavily favored Petro Gazz in the Premier Volleyball League (PVL) All-Filipino Conference quarterfinals on Tuesday at the Philsports Arena.

The upset victory put the Thunderbelles on the brink of a historic semifinal appearance, proving their mettle against the two-time Reinforced Conference champions.

Despite the Angels' experience, ZUS Coffee displayed poise and resilience, particularly in a pulsating third set. Rising star Chinnie Arroyo fearlessly traded blows with Petro Gazz ace Brooke Van Sickle in a thrilling endgame duel, while veteran Jovelyn Gonzaga delivered the clutch plays to seal the win.

"It must've been a good morning," said Michelle Gamit, who finished with 10 points, earning the Player of the Game honor.

"Everyone wanted to win, and thank God, all our hard work in training paid off."

Chai Troncoso led the Thunderbelles' attacks with 14 points, while Gonzaga and Thea Gagate contributed 11 apiece.

Van Sickle placed Petro Gazz with 18 points, while Myla Pablo added 14, though costly errors down the stretch proved costly.

With game 2 set for Saturday, the Angels must regroup quickly to avoid a stunning early exit at the hands of the league's biggest revelation.