Phelps, Lochte showdown in 200m medley
Both of them breezed into the final Wednesday with Lochte the fastest and Phelps third overall, Xinhua reports.
Phelps had a slight advantage over Lochte after the butterfly and backstroke in the semifinal, and they were even coming out of the turn at the 100m mark.
Lochte pulled ahead in his breaststroke leg, and raced home to top the group in 1 minute and 56.13 seconds. Phelps clocked 1:57.11.
Other strong competitors competing for gold include Hungary's Laszlo Cseh, runner-up at Beijing Games, and Brazil's Thiago Pereira, who got a silver in the 400m individual medley Saturday.
Cseh, who failed to qualify for the 400m individual medley final with a ninth place behind Phelps, aims a revenge in the 200m final.
Phelps, with a record 19 Olympic medals and 17 world championship gold medals already in his possession, is the most prolific Olympic medallist.
His three medals in London - one gold and two silver - helped him surpass former Soviet gymnast Larisa Latynina's record 18 career Olympic medals.
After failing to defend his 200m butterfly and 400m individual medley at London Olympics, Phelps is eyeing a third straight Olympic gold in the 200m medley.
Phelps failed to win a medal in the 400m individual medley, finishing fourth on the opening day, when Lochte took the gold.
Then Tuesday, a glide to the wall cost Phelps another chance for gold. South African swimmer Chad Le Glos capitalised on Phelps' sloppy finish to win his country's first swimming gold in London.
Phelps and Lochte, overwhelming favourites for Thursday's contest, have had victories against each other.
Lochte emerged from Phelps's shadow with five titles at the World Championships in Shanghai -- including 200m freestyle and 200m individual medley victories. But Phelps sent an undeniable message to his biggest rival by beating him in three out of four events at the U.S. Olympic trials in June.