Rome:Michael Phelps already has a strong contender to deal with in Germany's Paul Biedermann. Milorad Cavic is lurking, too.
Biedermann soundly beat Phelps in the 200-meter freestyle heats and semifinals on Monday and Cavic won the gold medal in the 50 butterfly, which Phelps did not enter.
"It's great to be the world champion in the 50 fly. But I'm so completely focused on the 100 fly, it's tough to get excited about this right now," Cavic said. "I have to keep going but this is a great confidence booster"
At last year's Beijing Olympics, Cavic came closer to beating Phelps than anyone else.
The American-born Serb lost by a mere hundredth of a second, a finish so close that the Serbs filed a protest and swimming's governing body had to review the tape down to the 10-thousandth of a second.
Phelps won because he applied the necessary three kilograms (6.6 pounds) of pressure to activate the finish touchpad, while Cavic did not.
"He thought it was enough to win, but now he knows that you need three kilograms of pressure," said Andrea Di Nino, Cavic's new coach. "That's where he lost, but you can't really work just on that. He can't put all his focus on the finish. Milorad has to win in the first 50."
The 100 fly heats and semifinals are scheduled for Friday, with the final on Saturday.
After the Olympics, Cavic ended a seven-year spell working with coach Mike Bottom in California, deciding he wanted to move to Serbia.
"I needed a change of environment. I was planning on training in Belgrade but the roof of our pool caved in," Cavic said, explaining that he then looked for the closest option to Serbia, and ended up with Di Nino in San Marino.
Butterfly specialists from Slovenia, Russia and Venezuela also work with Di Nino.
"It's a little different than what I'm used to but it's working," Cavic said. "There's more than one way to do something correctly, and I think I've been doing something positive."
Cavic joined Di Nino's program in October and won the 100 fly at the European short-course championships two months later.
"It doesn't take him long to get in form," Di Nino said. "But he can't go into the race thinking only about Phelps. This is one of the most competitive races in the pool."
Olympic bronze medalist Andrew Lauterstein is also in Rome, and both he and Cavic wear the new 100-percent polyurethane bodysuits that have been responsible for 11 world records in the first two days of pool events.
"I'm really looking forward to it. Cavic shows that he's swimming well at the moment," Lauterstein said. "That's my main event in this meet."
Cavic dons the Arena X-Glide and Lauterstein has the Jaked 01, while Phelps is sticking with last year's LZR Racer from Speedo.
"Last year it was me and a lot of people blaming Omega for not having a better technology because I did touch the wall first," Cavic said. "Now if I was to beat Phelps, they would say: 'Cavic beat Phelps because of the suit.'"
Phelps broke Ian Crocker's four-year-old world record at the US Championships in Indianapolis earlier this month, clocking 50.22 seconds.
"I thought he was going to go under 50 seconds. He didn't but I know that he will here," Cavic said. "But it's not about what he's going to do. I'm going to do what I need to do and hopefully it will be better.
"I'm not afraid of him. I've proven that I'm not someone who stands down. A lot of people have this mental block that Michael Phelps cannot be beat. I think he can be beat."