Merritt won the 400 m at the 2008 Summer Olympics in Beijing. A close race between Merritt and Wariner was expected, though it ultimately ended in a rout. The 0.99-second margin between Merritt's first-place finish and Wariner's second-place finish was the largest in an Olympic 400  m final. His time of 43.75, a new personal best, made him the fifth fastest 400  m runner on the all-time lists, still two places behind Wariner, who is third on the all-time list of fastest runners. He teamed up with Wariner, Angelo Taylor and 400  m bronze medallist David Neville for the men's 4 × 400 m relay. The team defeated the Olympic record mark which had stood since the 1992 Barcelona Olympics by running a time of 2:55.39, the second fastest in the history of the event.