Hanover moved up to 54 points with four games left while champions Bayern, fourth with 52, host second-placed Bayer Leverkusen on Sunday.
The visitors, who saw Mohammed Abdellaoue’s effort cleared on the line after 15 minutes, had no trouble keeping Hamburg at bay but were made to work hard to carve out only a few real scoring chances themselves in a very physical game.
Both teams came agonisingly close late in the second half with Hanover’s Didier Ya Konan firing just wide in the 76th minute and Hamburg midfielder Eljero Elia’s shot seconds later cleared off the line.
VfL Wolfsburg, the 2009 Bundesliga champions, needed an 89th minute goal from Jan Polak to snatch a 2-2 draw at home relegation rivals St Pauli.
Both teams are on 29 points with Wolfsburg in 16th place, the relegation playoff spot, on goal difference from St Pauli, who are 17th and in the danger zone.
VfB Stuttgart, long stuck in the bottom places themselves, continued their timely recovery by winning 3-1 win at Cologne to move up to 33 points, four clear of Wolfsburg.
Champions League semi-finalists Schalke 04 take on Werder Bremen later on Saturday as they look to win their fifth straight game under new coach Ralf Rangnick.
Bundesliga leaders Borussia Dortmund, on 66 points, host Freiburg on Sunday