Harper, who hit 16 homers in the first two rounds, led off the final round. The 20-year-old, who was receiving pitches from his father Ron Harper, went deep on the first three swings of the final round. Harper finished the round with eight homers, his third straight round with exactly eight home runs.
Cespedes, who hit 23 homers in the first two rounds, stepped up to the plate after Harper. The outfielder smashed a line-drive homer on his first swing of the final round, and blasted his second homer of the round 411 feet on his third swing. The right-hander continued his power display, hitting his ninth homer with five outs to go.
The slugger becomes the second Oakland hitter to win the HR Derby; Mark McGwire was crowned champion in 1992. Cespedes is the fourth straight AL player to win the Derby; Prince Fielder was the last NL player to win the Derby as a member of the Milwaukee Brewers in 2009.