Colorado missed a great chance to go ahead in the 1-th minute when Cummings overhit a pass to Conor Casey on a two-on-one break in the 10th minute. Cummings then missed a second chance in the 21st minute, sliding a shot well wide of the left post.
But it was a case of third time lucky for Cummings in the 24th minute. His pass was deflected in front of the goal and right to Mastroeni, who easily beat Columbus goalkeeper Andy Gruenebaum.
The Rapids had further chances to increase their lead in the first half as first Cummings missed with a header in the 31st minute and then Wells Thompson hit the side netting after breaking free in the 39th minute.
Colorado had a 10-1 shot advantage in the first half and that domination continued after the interval when Cummings misfired on a header early in the second half.
Even with all that domination, the Rapids could not get a second goal and the Crew almost stole the game late as Colorado goalkeeper Matt Pickens had to make a good save to deny Andy Iro’s header in the 84th minute.