Intro:

Kei Nishikori, Roger Federer, Alejandro Falla and Philipp Kohlschreiber all progressed to the Gerry Weber Open semi-finals in Halle, Germany, on Friday.

Script:

The quarter-finals of the Gerry Weber Open in Halle, Germany, on Friday.

First on centre court was Columbian Alejandro Falla and Munich-born Peter Gojowczyk.

In a predictably close match, Gojowczyk broke the world number 69 and wrong-footed him in the process.

Falla recovered to win the first set tie break and it was a similar story in the second; the 30-year-old edging it 7-6 7-6. Falla now has another German, Philipp Kohlschreiber, lying in wait in the semi-finals.

The Bavarian defeated Rafael Nadal's conqueror and fellow German Dustin Brown in three sets.

Kohlschreiber went on the offensive and claimed the opening set.

Brown eventually levelled the match at one set all, before the final set went to a tie-break.

Both players blew a combined 11 match points but it was Kohlschreiber who booked his place in the last four.

Kohlschreiber -- whose father worked at a petrol station -- will hope he has enough in the tank to win the Halle title he last won three years ago.

Japan's Kei Nishikori is lying in wait on the other side of the semi-final draw after he knocked out American Steve Johnson.

The Madrid runner-up won this point after Johnson slipped on the way to taking the first set.

The second went to a tie-break which Nishikori won to set up a showdown with Roger Federer in the semis, whom he's beaten in their last two meetings. The Swiss' opponent, Yen-Hsun Lu, withdrew with a back injury.