DENVER — A little rest seems to do wonders for Nolan Arenado.The Colorado Rockies’ third baseman has not been in the lineup four times this season and on each occasion, the breather has resulted in a productive game.Never more so than Wednesday when Arenado hit three home runs in a game for the first time in his career as the Rockies walloped the San Diego Padres 18-4 to sweep their three-game series and win their fourth in a row overall.Arenado had a career-high five hits and tied a personal best with seven RBIs. He also scored four runs.Arenado’s memorable game gave him 21 homers and a major league-leading 80 RBIs this season. With a shot at a record-tying four homers when he came to bat in the eighth, Arenado ran the count to 3-2 and lined out to left.In four games after not being in the lineup, Arenado has gone 12-for-20 (.600) with one double, four home runs and 13 RBIs the next day.Trevor Story and Charlie Blackmon also homered for the Rockies, who reached season highs in runs and hits (21). Story also had three hits, three RBIs and scored three runs. Blackmon had three hits, two RBIs and scored three runs.The Rockies lost 15 of 20 games from June 21-July 15, scoring three or fewer runs in 12 of those defeats. But they have emphatically put that dismal offensive stretch behind them, scoring 49 runs in their four straight wins while yielding 21.The Rockies, who lead the majors with 25 wins in day games, scored in each of the first seven innings and strafed Padres starter Clayton Richard (5-10). He allowed career highs in both hits (14) and runs (11) while throwing 100 pitches in 3 2/3 innings.Rockies starter Jon Gray (3-1) pitched six innings. He blanked the Padres for the first five before they scored four in the sixth, three on Cory Spangenberg’s seventh homer.The Rockies hit three homers in their six-run fourth that blew the game open and gave them a 12-0 lead. Arenado led off the uprising with the first of his three homers. With two outs in the inning, Story belted his 12th home run, a two-run shot that followed Gerardo Parra’s broken-bat single.Gray singled home Ryan Hanigan, who hit a ground-rule double, and Blackmon greeted Kevin Quackenbush by driving his pitch over the fence in center for a two-run shot, his 23rd homer of the season.The Rockies took a 3-0 lead in the first. Arenado singled home the first run after Blackmon led off with a bloop single to short left and DJ LeMahieu walked. A passed ball by catcher Hector Sanchez and Ian Desmond’s sacrifice fly netted the other two runs.Arenado’s two-out single in the second made it 4-0. Two more runs in the third put the Rockies ahead 6-0. Story’s first triple of the season followed Parra’s one-out single, and Story scored when Hanigan singled up the middle with the infield drawn in.Parra went 4-for-5 and had extended his string of reaching base to 10 consecutive at-bats before he flied out in the fifth. His string of consecutive games with an RBI ended at eight, but in nine games since being reinstated after a 28-game stay on the disabled list, Parra is 17-for-33 (.515) to raise his average to .364.NOTES: Rockies CF Charlie Blackmon extended his hitting streak to a season- and career-high-tying 14 games. … Rockies RHP Chad Bettis (testicular cancer) is scheduled to pitch Sunday for Triple-A Albuquerque and work four innings or 60 pitches in his third rehab start after two with Double-A Hartford. … Rockies RHP Tyler Chatwood (right calf strain) threw his first bullpen session since getting injured Saturday. … Padres OF Franchy Cordero was recalled from Triple-A El Paso, and RHP Jose Valdez was optioned to that team. … Padres OF Hunter Renfroe (strained neck) is expected to be activated Thursday when he is eligible to be reinstated. … Padres OF Travis Jankowski (right foot bone bruise) is scheduled to play nine innings Wednesday and Thursday nights in the Arizona Rookie League and travel Friday to another Padres affiliate to continue his rehab. … Padres RHP Jarred Cosart earlier this week underwent season-ending arthroscopic surgery on his right elbow.