Jose Paolo Guerrero scored twice in four second-half minutes to move Hamburg one point behind Bundesliga leaders Hertha Berlin following victory at Schalke.
Guerrero bagged his seventh and eighth goals of the season in the 71st and 75th minutes to give Hamburg a 2-0 lead.
Schalke pulled a goal back through Jefferson Farfan in the 80th minute, but it would prove a consolation strike as the visitors moved into the thick of the title race.
Hamburg are now level on points with Bayern Munich and Wolfsburg on 48 points with Hertha, who lost at Stuttgart yesterday, just a point clear.
Schalke are 11 points further back and will now surely contend themselves with trying to catch fifth-placed Hoffenheim - who are seven points better off - for a place in Europe.
Schalke had the ball in the net after 14 minutes, but Jermaine Jones was ruled offside after his left-foot shot from six yards.
Schalke nearly broke the deadlock in the 27th minute when Heiko Westermann's shot was deflected by Dennis Aogo, but Frank Rost just did enough to get a hand to the ball a make the stop.
Hamburg's only chance of the half came following a Schalke mistake after 31 minutes.
Aogo's wayward cross should have been easy for Levan Kobiashvili to deal with but instead he fluffed his header back goalkeeper Manuel Neuer, allowing Jonathan Pitroipa to get in between them.
Pitroipa failed to convert his chance though, shooting five yards over the crossbar.
Schalke had another goal ruled out for offside six minutes before the break, Vicente Sanchez this time denied the opener, before Kevin Kuranyi headed just over as the game remained scoreless.
Hamburg finally scored the opening goal after 71 minutes following a blunder from Neuer.
The goalkeeper rushed out to collect a long ball, but was forced to leave his area to deal with it and could only head into the path of Guerrero who slotted into the empty net.
Guerrero made it 2-0 just four minutes later on a counter attack when Daniel Jensen crossed to the back post where Guerrero converted from three yards.
Schalke got what would prove to be a consolation goal with 10 minutes to play when Kuranyi ran down the left and crossed to the far post where Farfan volleyed in from three yards.
