Quaison opened the scoring in the 10th, tapped Mainz's third in the 19th and completed his treble in the 40th on Tuesday.

The second goal in the 15th highlighted Bremen's woes as a miscued clearance attempt from Milos Veljkovic hit the inside post and then went in off goalkeeper Jiri Pavlenka's back.

Jean-Philippe Mateta completed the scoring in the 82nd.

Bremen offered little resistance, with Leonardo Bittencourt denied by the post and a goal from veteran Claudio Pizarro disallowed for handball.

They suffered their joint third-heaviest home defeat in the Bundesliga.

Bremen's crisis deepened after a 6-1 debacle at champions Bayern Munich, but club officials have voiced their full support for coach Florian Kohfeldt.

Bremen have won just once in their last 12 games, are two points above the danger zone in 15th but could slip to second-last by the end of the midweek round.

Mainz, by contrast, have won three of their five games under new coach Achim Beierlorzer and moved four points clear of Bremen into 13th.

Three further matches are scheduled later on Tuesday, with leaders RB Leipzig at third-placed Borussia Dortmund.

The other five games are on Wednesday and include champions Bayern Munich in Freiburg.

Australian Associated Press