Three of the top four seeds have advanced to the semifinals of the Roanoke Valley Invitational Tennis Tournament men's open singles division, none more easily than top-rated Martin Sayer.

Sayer, who is using this event as a tune-up for next month's Davis Cup, lost just one game in his two matches Saturday. He defeated Cliff Gaddy 6-0, 6-0 in the round of 16 and dropped No. 5 seed Elliott Datlow 6-1, 6-0 in the quarterfinals.

"Yeah," said Datlow, an assistant women's coach at Washington and Lee. "He's good."

Sayer will face fourth-seeded Jakob Gustafsson at 9 a.m. today at Hollins University. Gustafsson defeated Malik Mubeen -- the two-time Group A champ from Radford High -- 6-4, 6-3 before knocking off former RU standout Brandon Johnson 6-2, 6-4 in the quarters.

Today's other 9 a.m. semifinal pits former Virginia Tech player Ignaci Roca, the No. 3 seed, against seventh-seeded Sergio Wyss. Wyss upset No. 2 seed Nicolas Delgado de Robles in the quarterfinals.

The final is scheduled for 11:30 a.m.

One of the most exciting matches of the day featured 16-year-old Patrick O'Keefe against Datlow in the round of 16. O'Keefe, the reigning Group AA champ from Salem High, won the first set 6-2 before dropping the second by the same score. By rule, the competitors played a race to 10 points in lieu of a third set, which Datlow won 10-4.

"He was a strong player," Datlow said. "He was a lot of fun to play. He came up roaring and ready to go, and I had to work my way into it today. He battled me."

O'Keefe -- who lost in the first round of the RVITT last year -- was pleased with his effort against a player 12 years his senior.

"After that first set, I was like, 'Gosh man, I could play Martin,' " O'Keefe said. "That would be awesome. We all look up to Martin. He's great. I was trying not to think ahead, but I did at the same time."

Sayer is the prohibitive favorite among the players moving forward.

"I've seen him play. He's insane," O'Keefe said. "He looks like he's doing nothing. It's so easy for him."