Lu, Edmund among winners in ATP Delray Beach openers

British eighth seed Kyle Edmund and Taiwan's Lu Yen-Hsun booked a second-round matchup on Monday at the ATP Delray Beach Open while US defending champion Sam Querrey advanced on a retirement.

Edmund, ranked 49th, fired five aces and faced only one break point in a 6-3, 6-0 victory over France's Adrian Mannarino, while Lu, ranked 63rd, rallied from a set and 0-3 down to defeat American Bjorn Fratangelo 4-6, 7-5, 6-4.

"It was a tough feeling in this moment," Lu said. 

"I just tried other things. I changed the game plan, trying to come into the net more and put the pressure on him. I had nothing to lose. I just tried to play a different way and see how he reacts. It worked pretty well after that."

Fourth seed Querrey advanced 6-2, 2-1 when Israeli rival Dudi Sela retired with a back injury. The 35th-ranked American improved to 14-7 at Delray Beach.

In a showdown of 19-year-old prodigies, American Taylor Fritz defeated Japan's Akira Santillan 6-4, 6-4. Fritz next faces either compatriot Donald Young or Croatian second seed Ivo Karlovic.

Japan's Yoshihito Nishioka ousted Belgium's Kimmer Coppejans 6-3, 6-3, sending him into a second-round match against either US fifth seed Steve Johnson or American wild card Stefan Kozlov.