LONDON (AP) -- Felix Sanchez dominated the 400-meter hurdles at the beginning of the last decade, earning the nickname "Super Sanchez."
The Dominican was virtually unbeatable - winning 43 consecutive races, two world championships and a gold at the 2004 Athens Games.
Less than a month before he turns 35, Sanchez is looking for a second gold medal Monday when he races in the 400-meter hurdles final at the London Games. Given his age and poor results in recent seasons, that possibility was almost unfathomable not too long ago.
Sanchez won his semifinal in an impressive 47.76 seconds, the world's best time this year, and just 0.13 seconds slower than when he won gold in Athens.
"I've demonstrated to the world that I'm back," Sanchez said.
He added that he is free of the injuries that plagued him in Beijing, when he was eliminated in the heats.
If he's victorious Monday, Sanchez will become the oldest athlete to win a race of 400 meters or less at the Olympics. It's a big "if," and his biggest obstacle is a runner from a neighboring Caribbean island.
Javier Culson, a 28-year-old Puerto Rican, won silver at the world championships in 2009 and 2011, and has four victories this season in the Diamond League.
Culson has the opportunity to provide Puerto Rico with its first-ever Olympic gold medal.
"All of the support I have received has moved me, and to see how everyone has become united," Culson wrote on his Twitter account. "All the years of effort, sacrifice and dedication have come down to this moment."
British runner Dai Greene is also a contender despite a poor semifinal performance, coming in fourth with the second-worst time. But Greene beat Culson at the 2011 world championship in Daegu, South Korea.