Geraldo Perdomo hit a grand slam Wednesday night and Brandon Pfaadt sailed through the longest start of his career as the visiting Arizona Diamondbacks cruised to an 8-2 win over the San Diego Padres. Pfaadt (9-6) looked nothing like a pitcher who entered the night with a 5.42 earned run average, going eight innings while allowing two runs on four hits. Pfaadt walked none and fanned four, slipping a called third strike past Fernando Tatis Jr. with his 99th and final pitch of the game. Perdomo blew open a 2-0 game in the top of the fifth, lining his 10th homer of the year and Arizona’s MLB-high ninth slam of the season into the right field seats.