Jansen said that following his side's dominance in the final 30 minutes they should have ended up taking three points instead of one.
"It's a shame we couldn't achieve what our performance in the final 30 minutes deserved," Bundesliga.com quotes him as saying.
"Ultimately, we have to settle for a point, which isn't enough considering we had five or six great opportunities that fell to several players.
"I have to try to come to terms with this result over the next couple of days, then we have to focus our attention to the cup game on Tuesday."
Hamburg are 11th in the Bundesliga.