SAN ANTONIO -- Barely breathing hard, Michael Phelps turned in his best performance in the 200-meter butterfly since the 2012 London Olympics.

Now, he wants to go even faster.

Phelps easily led the preliminaries at the U.S. national championships in 1 minute, 55.15 seconds on a sweltering Friday morning in Texas.

His time would have been third-fastest of the qualifying heats at the FINA world championships in Kazan, Russia -- the measuring stick for Phelps' performances in San Antonio.

"It felt like a normal swimming swim," said Phelps, who shaved down after growing a beard the last three months. "It still feels really weird to swim without a beard. That felt really weird when I dove in this morning."

The winningest athlete in Olympic history was barred from worlds as part of his punishment for a second drunken-driving arrest. So he's treating nationals as his biggest meet of the year, looking to post times that would have been good enough to put him on the top of the podium in Kazan.

His target for the evening finals: Laszlo Cseh's winning time of 1:53.48 in the 200 fly.

"I felt good," Phelps said. "The stroke felt decent. It's a good morning swim. I don't know how many times I've gone 1:55 low in the morning."

Phelps' coach, Bob Bowman, was impressed not only with the time the swimmer posted, but that it didn't look like it required maximum effort. His second 50 split was 28.93, followed by a 29.82 on the third lap, and a closing 30.48 as Phelps clearly backed off, gliding to the wall more than a second ahead of the next-fastest swimmer, Jack Conger.

"I'm very happy with that," Bowman said. "I think it's one of his best prelim times."

After coming out of retirement in 2014, Phelps initially resisted swimming the 200 fly. He was dreadfully slow at a May meet in Charlotte, looked better the next month in Santa Clara and has clearly put in some of the most serious training of his career leading up to nationals.

Phelps' time was actually faster than his prelims swim in London (1:55.53), though the format in San Antonio is different. There are no semifinal heats, as there are the Olympics and worlds, so Phelps will have to drop a significant amount of time in the evening to eclipse Cseh's gold-medal performance in Kazan.

Phelps is clearly on many swimmers' minds even though he's not at worlds. South African Chad le Clos, who stunned Phelps in the 200 fly final at London, finished second to Cseh in that event at worlds.

"I wish that he was here," Le Clos said of Phelps. "He's been talking a lot of smack in the media about how slow the butterfly is, so I just can't wait until I race him again. I'm going to really go for his world record next year."

Phelps still holds the 200 fly mark of 1:51.51, set at the 2009 worlds before high-tech, rubberized suits were outlawed.

"He's definitely pushed when people say things," Bowman replied, breaking into a sly smile. "We'll see how all that pans out."