Australia's "Special Ks" Nick Kyrgios and Thanasi Kokkinakis have grabbed the attention at the Australian Open with top players and coaches lauding them as exciting members of a new generation.
Both teenagers caught the eye in reaching the second round, with 17-year-old Kokkinakis praised by world number one Rafael Nadal and Kyrgios, 18, going down guns blazing in an absorbing five-setter.
Nadal said Kokkinakis has everything to become a great player after the youngster went down in straight sets, impressing with his serve and forehand.
"He has a great serve for a 17-year-old and he will serve better and better every year. He has a good forehand. So he will have the chance to be a great player. He has everything to do it," Nadal said.
"The normal thing is if he is able to improve while being humble, as long as he has the right people around him that don't make him feel a star before the right time."
Kyrgios showcased his enormous potential in an engrossing five-set duel with French 27th seed Benoit Paire, which lasted three hours 20 minutes and went into the early hours of Friday morning.
Flashy Kyrgios won the first two sets in tiebreakers but could not withstand Paire's fightback, but for one so young it was an encouraging performance.
Kyrgios was described by the local media as giving a "performance both electrifying and brave", while American Paul Annacone, who once coached Roger Federer and Pete Sampras, tweeted: "Aussie men have some youngsters with big potential -- excited to see where they go."
Respected commentator and coach Darren Cahill said the emergence of Kokkinakis and Kyrgios could work against Australia's as yet unfulfilled talent Bernard Tomic, 21, who was booed for his injury retirement against Nadal in the first round.
Cahill, the former coach of Lleyton Hewitt and Andre Agassi, said Tomic will be aware he could soon be overtaken by the younger local talents.
"This could be the best thing for him (Tomic), because a lot of the contracts will start drying up if he has his ranking around 50, 60 at the end of this year, and with these young guns coming through, the attention will go to that next generation," Cahill said.
Patrick McEnroe, the general manager of player development at the US Tennis Association, said he had been impressed by the attitude of teen duo, dubbed "Special Ks" in the media.
"These guys seem to love the stage, love to be out there, and this could be the best thing that could ever happen to Tomic, because he has showed flashes of brilliance on the court, especially down here," he said on ESPN.