World champion LaShawn Merritt settled for second place behind rising star Machel Cedenio in the 400m at the Ponce Grand Prix athletics meeting.
Trinidad and Tobago’s Cedenio, the 2014 world junior champion, won the one-lap race in 44.97sec, while America’s Merritt, winner of world titles in 2009 and 2013 and Olympic gold in 2008, clocked 45.42sec.
Third place went to Dominican Gustavo Cuesta (45.89).
Two other marquee names failed to shine in the event. Dominican Luguelin Santos, the 2012 Olympic silver medalist, finished fifth in 46.19sec, while US veteran Jeremy Wariner was sixth in 46.22.
Wariner, Olympic gold medalist in 2004 and world champion in 2007 and 2009, is trying at the age of 31 to relaunch his career after three seasons disrupted by injury.
He was part of the winning US 4x400m relay team at the IAAF World Relays in Nassau earlier in May.
Puerto Rican star Javier Culson gave home fans little to celebrate. The 2012 Olympic bronze medalist in the 400m hurdles was beaten by Jeffery Gibson of the Bahamas.
Jason Richardson, America’s 2012 Olympic silver medalist in the 110m hurdles, won his event in 13.34sec, holding off Cuba’s Yordan O’Farril (13.35).