Borussia Moenchengladbach missed the chance to join Borussia Dortmund at the top of the Bundesliga after their 1-1 draw against Hamburg.
'Gladbach took the lead at home on the stroke of half-time through Mike Hanke, but the visitors hit back soon after the break, with Tolgay Arslan smashing the ball past Marc-Andre ter Stegen from close range.
The first-half started off slowly, with both sides eager to give nothing away, but eventually, chances began to be crafted with Arslan forced a solid save from ter Stegen from the edge of the area.
Igor De Camargo scuffed a presentable opportunity, running on to a chipped ball from Hanke, but his ball across the face of goal was tame and easily cut out for a corner.
Reus swung in the resulting set-piece, which Roel Brouwers met brilliantly at the far post, but unfortunately for Lucien Favre's side, Dennis Diekmeier was well-stationed on the line to clear the Dutchman's shot away.
Juan Arango shot narrowly wide as the hosts searched for the opener, before a second inopportune slip from De Camargo stopped the Belgian from putting his side ahead.
Finally Arango curled in a brilliant free-kick which Hanke met, sending the ball into the bottom corner. Hamburg appealed for an offside, perhaps justifiably, but no such decision was forthcoming.
Far from being shell-shocked by falling behind so late in the first period, the visitors came out from the break with renewed vigour.
Guerrero cut in from the left before feeding Arslan, who swiped at the ball, sending it comfortably over the bar when he should have done better.
Minutes later the ball broke to Marcel Jansen at the edge of the box after some suspect defending from the hosts, but he could only send the ball straight at ter Stegen.
Some excellent defending from Brouwers prevented Guerrero from latching on to a set-piece, but from the resulting corner, Hamburg scored.
Guerrero met Aogo's delivery, padding the ball into Arslan's path. The Turk swivelled, and blasted the ball into the bottom corner from just inside the six-yard box.
Arango missed a great opportunity to clinch all three points for the hosts in the dying moments, sending Reus' corner comfortably wide after being found completely free in the area.
The draw means a victory for either Bayern Munich or Schalke on Sunday will see them overtake Borussia Moenchengladbach in second place.