Trevor Story and Nolan Arenado homered, David Dahl had three hits and two RBIs, and the host Colorado Rockies beat the Arizona Diamondbacks 10-3 in Denver on Thursday afternoon.Kyle Freeland allowed three runs 6-1/3 innings to help the Rockies extend their National League West lead to 4 1/2 games over third-place Arizona. Colorado leads the Los Angeles Dodgers by two games. The Dodgers play later Thursday in St. Louis.Arizona starter Clay Buchholz was scratched just before first pitch with what the team said was tightness in his right elbow. Matt Koch (5-5) started in his place but was roughed up for four runs on eight hits in three innings.Freeland (15-7) gave up just two hits in the first six innings before running into trouble in the seventh. With one out Steven Souza Jr. tripled and Nick Ahmed doubled. Yencey Almonte relieved Freeland and allowed an RBI double to Ketel Marte that closed the gap to 5-3 before getting the final two outs.Colorado responded with five runs in the bottom of the inning. Ian Desmond’s bases-loaded walk drove in one run and Charlie Blackmon, Dahl and DJ LeMahieu had consecutive singles to make it 10-3.Arenado started things with his 34th home run and second in as many nights to give Colorado a 1-0 lead in the first inning. A.J. Pollock tied it in the second inning with a leadoff homer, his 17th of the season, but Freeland’s RBI double off the wall in center gave the Rockies a 2-1 lead.