Zverev topples Goffin, Kohlschreiber too strong for Del Potro
Alexander Zverev's superb 2016 season continued as he knocked top seed David Goffin out of the BMW Open at the quarter-final stage on Friday.
Teenager Zverev has already climbed to a career-high ranking of 49 and was in superb form to reach his fourth ATP World Tour semi-final thanks to a 6-3 4-6 6-3 win.
Goffin, who had won the pair's only other career meeting in 2014, was broken twice in the first set, but survived seven second-set aces from Zverev to level the match.
However, Zverev lost just three points on serve in the decider and will now meet Dominic Thiem, who defeated Ivan Dodig 6-4 4-6 6-3.
On the other side of the draw, Juan Martin del Potro was beaten in straight sets by Philipp Kohlschreiber - a two-time champion in Munich who has also finished as runner-up in two of the last three seasons.
A solitary break in the first game was enough to put Kohlschreiber in front and the German duly reeled off six games in succession to triumph 6-4 6-1.
Awaiting Kohlschreiber in the last four is 2014 finalist Fabio Fognini, who held off a brave fightback from lucky loser Jozef Kovalik to prevail in three sets.