Friendship will be on the back burner when Roger Federer faces childhood mate Marco Chiudinelli in a battle of Basle boys for a place in the final of the Swiss Indoors.
Top seed Federer has won the last three editions of his home event, claiming his 18th straight victory at the tournament with a 55-minute win over Russian Evgeny Korolev 6-3, 6-2 Friday.
Number 73 Chiudinelli, who will be playing the first semi of his career, defeated Richard Gasquet 6-1, 6-3.
The dream scenario in the hometown of both men will be the first for the pair who played as rivals on the football pitch and for a time lived on the same street.
"Marco has really been improving this year. It will be tough but enjoyable," said Federer. "I hardly ever get to play a good friend like this. It should be a great experience, I'm looking forward to it."
Second seed Novak Djokovic salvaged his successful debut week, recovering from a set and a break down to oust sixth seeded Swiss Stan Wawrinka 3-6, 7-6 (7-5), 6-2.
The Serbian will next face Czech Radek Stepanek, a 4-6, 6-3, 6-3 winner over Croatian fourth seed Marin Cilic.
Cilic's loss leaves him with a huge task if the provisional 12th-placed player is to stay in the race for one of two remaining places in the eight-man season final in London later in the month.
Djokovic has won four of five matches against Stepanek, including a US Open fourth round two months ago.
The victory in just over two-and-a-quarter hours was markedly more laboured than the 6-0, 6-0 rout Djokovic inflicted 24 hours earlier on luckless Czech Jan Henrych, the first "double bagel" of his career.
"This was much more than just a test," Djokovic said of the Wawrinka win.
The Serb ranked fourth in the world but with a chance to climb to second given the right circumstances as the ATP season nears an end, got a break back in the eighth game as he began to turn the tide against Wawrinka, whose six-months-pregnant girlfriend was cheering him on from the box.
Djokovic won a second-set tiebreaker to stay in the chase, then ran away with the third set on the back of two quick breaks that left Wawrinka with few hopes as the Swiss saved one match point but couldn't handle a return at his feet on the second.
"I served well and got a lot of balls back from 4-3 in the second set (when he then broke back for 4-4). I had some good luck in the tiebreak, then the third set was another story."
Djokovic said the contest was decided on a handful of points. "I held my nerve in those moments. I was able to play every point and wait.
"I didn't feel so great at the start, I needed time to get my engines running," said the 22-year-old. "At the start it was tough for me to get moving."