Bastian Schweinsteiger put the hosts ahead against the run of play in the 12th minute before Lukas Podolski added a second from the penalty spot four minutes later.

But a 25th-minute strike from Guerrero and a penalty converted by Trochowski in the 57th minute earned Hamburg a deserved draw.

The result means Hamburg remain unbeaten in four visits to the Allianz Arena while Jurgen Klinsmann's first match in charge of Bayern ended without the desired win.

Hamburg were quick out of the blocks and appealing for a penalty after just 11 seconds when Jonathan Pitroipa's cross struck the arms of Bayern defender Daniel van Buyten.

The appeal was turned down, but Hamburg kept their concentration with Ivica Olic and Guerrero both having chances

The lively Trochowski then swept a shot onto the far post of Michael Rensing's goal before the home side went ahead against the run of play in the 12th minute.

Ze Roberto cut in from the left wing and his cross deflected out to the edge of the penalty area where Schweinsteiger drilled a low shot past Frank Rost.

Within five minutes, Bayern doubled their lead from the penalty spot.

Joris Mathijsen was adjudged to have fouled Schweinsteiger, who was backing in to create room inside the penalty area, and Podolski swept the spot-kick home to give Bayern a dream start.

Hamburg coach Martin Jol looked concerned on the sidelines, but his team did not panic and continued to play the more enterprising football.

They were rewarded in the 25th minute when Guerrero rose to meet Trochowski's cross from the right and head low past Rensing.

Trochowski remained the dangerman as HSV grew in confidence, but it was the home side who went closest to restoring their two-goal advantage.

Miroslav Klose was sent through by Podolski and tried to take the ball around Rost, who stuck out an arm to deny the Bayern and Germany striker.

Bayern made the early running in the second half with Schweinsteiger's low cross being cleared off the line by Mathijsen before Podolski fired over the crossbar from just six yards out.

Hamburg should have scored their second in the 50th minute as Olic volleyed Trochowski's corner against the post, but that changed seven minutes later when referee Thorsten Kinhofer pointed to the spot for the second time in the game.

Trochowski stepped up to send Rensing the wrong way and level matters.

With 15 minutes remaining, Jol decided to protect a point by sending Timothee Atouba on for Pitroipa as his side began the season with an encouraging display.