Roger Federer has welcomed the emergence of Kyle Edmund and Chung Hyeon at the Australian Open in the absence of several high-profile players.
Edmund, 23, has risen to prominence following the pre-tournament withdrawal of fellow Briton Andy Murray, dumping out No 3 Grigor Dimitrov to become only the fourth British man to reach the last four in Melbourne in the post-1968 Open Era.
He will face 2014 US Open champion Marin Cilic on Thursday for a place in Sunday's final.
Federer faces 21-year-old Chung, who rocked the tournament with his upset of six-time champion Novak Djokovic.
"I think it's a good thing. They [Edmund and Chung] have got to make a move," said Federer, 36, who wrote to long-term rival Rafael Nadal on Tuesday after the Spaniard was forced to retire with a hip problem early in the fifth set of his quarter-final against Cilic.
"I find it disappointing when some of their breakthroughs come at 27, because then we know them for seven years, let's say. I like it when we don't know the guys.
"I like it because it's really something totally new to me and to some extent for you guys (media), too.
"It's not going to happen all the time. We like our rivalries that do exist on the tour. But new names are good, from time to time, of course for the tour."
Federer admits Edmund has now become a rival contender for the Grand Slam title, and urged the young Briton to seize his opportunity.
"Somebody who is in the semis, to me, is two steps away. A lot of stuff can happen. It's a good situation to be in," he said of Edmund.
"He can hit freely now. No expectations whatsoever. He'll maybe never be in this position ever again, to have so little expectations in some ways."
Federer, who is chasing his sixth Australian title, is looking forward to facing the bespectacled Chung for the first time for a place in the final.
"I'm very excited to play Chung. I thought he played an incredible match against Novak," he said.
"I mean, to beat him here is one of the tough things to do in our sport. I know that Novak maybe wasn't at 100 percent, but he was giving it a fight till the very end.
"To close it out, that was mighty impressive and shows that Chung's had good composure, a great mindset."