MELBOURNE, Australia (AP) _ The red line lapped at Michael Phelps' feet, as if pushing him to another world record.

A superimposed TV gizmo that demonstrates just how close swimmers are to record pace, the red line was actually moving along BEHIND Phelps as he approached the wall.

He wasn't chasing the mark. It was chasing him.

``That was amazing,'' said Phelps' coach, Bob Bowman.

At this point, Phelps is just racing himself and the records he already holds. On Wednesday at the World Aquatic Championships, he set his second world mark in as many days and showed no signs of slowing down with five more races to go Down Under.

``That's basically what he always does,'' Bowman said. ``That's how you improve the best.''

Can this be right? Phelps swam the 200-metre butterfly in one minute 52.09 seconds. In a sport where records are documented in hundredths of a second, Phelps broke his own record by a staggering 1.62 seconds _ the biggest drop in the record since 1959.

For those who thought the lanky American was at his peak during the 2003 worlds in Barcelona or the following year for the Athens Olympics, think again: He's better than ever, at the ripe ol' age of 21.

Phelps shattered the record he set just six weeks ago in Missouri. With the crowd at Rod Laver Arena rooting him on, he surged to the wall nearly two body lengths ahead of anyone else.

Whirling around and flipping up his goggles to get a better look at the scoreboard, Phelps squinted his eyes when the time flashed.

``I shocked myself,'' Phelps said. ``I heard the crowd the last 50 (meters). I didn't know how close I was or how far I was under it. You could tell by the expression on my face. I was shocked.''

In the stands, Bowman had a similar reaction.

Phelps' coach was keeping up with the split times, fully aware he was well below the pace of his previous record-breaking swim. But Bowman didn't truly grasp just how fast his star pupil was going until he glanced at the video board on the final lap.

The red line told it all.

``That was,'' Bowman said, struggling to find the right word, ``interesting.''

For Phelps, it seems like he's a kid again, breaking personal bests _ a.k.a. world records _ in seconds, not fractions of a second.

``I feel like I'm 12 years old, being able to drop more that a second off my best time,'' he said. ``I feel like an age-group swimmer again.''

Phelps can be downright boring when he speaks, rambling on about split times and underwater techniques.

But it's that singular focus that makes him the champion that he is. He gets up every morning thinking about the next swim, not the last one. Then, he blows everyone away.

``When I go into a race, I swim my own race,'' he said. ``I definitely do have competitors. I do have people that I want to race, people I want to beat. But when I get in the water, I'm trying to do a best time. I have to swim my own race to do a best time. I can't swim with someone else.''

No worries, Michael. No one can swim with you.

Just one day earlier, Phelps took down a swimming icon by beating Ian Thorpe's six-year-old record in the 200 free _ in Thorpey's home country, no less. After celebrating with a couple of sleeping pills, he was back at the pool early Wednesday for a preliminary swim in the 200 individual medley.

When he returned in the evening for the 200 butterfly final, but he didn't feel right.

``I actually felt like crap,'' Phelps said. ``I felt horrible in the warmup pool. I said to Bob, `I can still feel my arms from last night.'''

When it counted, Phelps blew everyone away, beating silver medallist Wu Peng of China by 3.04 seconds, an eternity in swimming terms.

``He is simply way too fast, way too fast,'' Wu said through a translator. ``I couldn't see him.''

Phelps was under world-record pace the entire race and extended his lead at every turn. At 100 metres, he dipped 1.65 seconds under his old mark. He stretched it to 1.78 seconds through 150 metres as the Aussie fans cheered louder and louder.

This is reminiscent of Phelps' performance at the 2003 world championships, where he set five world records _ two of them in different events on the same day, a feat no other swimmer had accomplished.

And, of course, Phelps is swimming the same eight events at the world championships as he did at the Athens Olympics, where he won six golds and eight medals overall. The plan in Melbourne is to show Phelps can win all eight and scuttle Mark Spitz's Olympic record _ seven gold medals in 1972 at Munich.

Well, it's three down and five to go.

``He's incredible,'' American teammate Katie Hoff marveled. ``He's just really in his prime right now. I think everyone thought it was at the Olympics or before that. But going to college and stuff, he's just doing some amazing things.''

Phelps had a bit of a letdown after Athens. He was arrested for drunken driving, moved away from home, enrolled at the University of Michigan and tasted the trappings of success. TV appearances. Parades. Even a beauty pageant (he was a judge, not a contestant).

After all that, he returned to what he loves best. The feel of the water against his skin. The burning of the muscles. The chance to touch the wall ahead of everyone else.

Phelps ramped up his training, working out even harder than he did before Athens. He hit the weight room, adding bulk to the shoulders of a sinewy frame that Bowman compares to a missile.

Now, he's doing things that no one has ever done.