Piedra burns 51s in game 1
The 28-year-old left fielder added a two-run double in the second, finishing 2-for-3 with a season-high four RBIs.
Piedra is batting .462 (6-for-13) with two homers since he was assigned to Sacramento by the Oakland Athletics on June 13. The former Rockies outfielder batted .279 in 141 games in the Majors over the last three years.
River Cats starter Kazuhito Tadano fanned six and walked two in 6 1/3 innings, surrendering three runs on six hits. Jeffrey Gray (2-3) retired the final two batters for the win, striking out one.
Las Vegas starter Spike Lundberg allowed three runs on eight hits and two walks in six frames. Matt Riley (1-1) retired one batter before serving up Piedra's homer.
Delwyn Young hit a solo homer in the first and Luis Maza and Octavio Martinez each contributed two hits for Las Vegas (29-38). -- Tim Leonard/MLB.com