He barely qualified for the evening final, a performance that hinted at trouble ahead. Trouble indeed. Phelps struggled to a fourth-place finish, blown out by Lochte and beaten by Brazil's Thiago Pereira and Japan's Kosuke Hagino.
''It was just a crappy race,'' Phelps said. ''I felt fine the first 200, then I don't know. They just swam a better race than me, a smarter race than me, and were better prepared than me. That's why they're on the medal stand.''
Lochte took the gold with a time of 4 minutes, 5.18 seconds. Pereira (4:08.86) and Hagino (4:08.94) were well back but ahead of Phelps, who touched fourth in 4:09.28 -- nearly 5 1/2 seconds off his world record from the Beijing Olympics and not nearly as fast as he went during the US trials last month.
Since finishing fifth in his lone event at Sydney, the 200 butterfly, Phelps was 16-of-16 when it came to winning medals at the Olympics -- 14 golds and two bronzes. That run is over.
Lochte climbed out of the pool with a big smile, waving to the crowd and looking about as fresh as he did at the start. He had predicted this would be his year and, for the first race of the Olympics at least, he was right on the mark.
''I think I'm kind of in shock right now,'' he said. As for Phelps, ''I know he gave it everything he had. That's all you can ask for.''
Phelps was trying to become the first male swimmer to win the same individual event at three straight Olympics. He'll have three more chances at a threepeat before he's done in London, having also won the 200 individual medley, plus the 100 and 200 butterfly, at Athens and Beijing.
But he'll need a major comeback. After one race, he looks nothing like the swimmer who won six gold medals in Athens, then a record eight in Beijing to break Mark Spitz's Olympic record.
''I'm surprised, and not pleasantly,'' Bowman said. ''I expected he'd be in the 4:06 range.''
With first lady Michelle Obama in the house waving a small US flag, everyone expected a duel between the two American stars.
Only Lochte showed up.