A great shot from Ivica Olic earned Hamburger SV a 2-1 win over Werder Bremen in Sunday's only Bundesliga match.
Guerrero put Hamburg in the lead with a right-footed shot after just six minutes but Brazilian striker Diego levelled from a free kick in the 24th.
But the home side got their winner with 16 minutes to go in regular time. Croatian Ivica Olic struck from the corner of the penalty area and the ball beautifully sailed in near the post.
Werder attempted to level again in the remainder of the match but Hamburg held on to their lead.