Schalke's Ahmed Kutucu had given them the lead in the 63rd minute but midfielder Gjasula rescued a point for bottom-of-the-table Paderborn when he scored with a powerful header from a corner with nine minutes remaining.
Sweden international Quaison earned Mainz a valuable away win, scoring in the 17th and 82nd minutes before a Dedryck Boyata effort gave Hertha some hope. Quaison, however, netted his third from the spot in the 90th minute to put the game beyond doubt.
A Luca Waldschmidt penalty gave Freiburg a narrow 1-0 win at home to Hoffenheim, while Wolfsburg had Marin Pongracic sent off as they drew 1-1 with Fortuna Duesseldorf and Marius Bulter scored twice as Union Berlin beat second-from-bottom Werder Bremen 2-0.
UEFA Nations League
De Bruyne may miss Belgium games for birth of child
Bayer Leverkusen host Borussia Dortmund in Saturday's late game, while leaders Bayern Munich and second-placed RB Leipzig meet on Sunday, as do Borussia Moenchengladbach and Cologne.
Hot-shot striker Lautaro Martinez attracts interest from a Premier League club - Euro Papers
Haaland double earns Dortmund win over Leverkusen in season finale
Dortmund cruise past Mainz to book Champions League spot