Squaring off for the very first time, the Colorado Rapids fell to Atlanta United FC, 1-0, on Saturday night in front of 44,938 fans at Bobby Dodd Stadium.

Rapids head coach Pablo Mastroeni opted for a starting eleven that featured six roster changes from Wednesday night’s defeat to the LA Galaxy, and his selection was initially rewarded as the Rapids looked lively out of the gate, playing with confidence and getting forward with regularity.

The tides began to turn midway through the first half, however, the home side settled in to a sustained spell of possession, only to be caught out on a 29th-minute counter-attack when Rapids winger Joshua Gatt made a tremendous 50-yard end-to-end run and nearly connected with forward Caleb Calvert on the back post.

The Rapids came close again in the 39th-minute when Dillon Serna almost caught goalkeeper Alec Kann off his line, but his 35-yard chipped effort caromed off the cross bar.

Just minutes later it was Gatt again who threatened to give the Rapids the lead, firing a left-footed drive from an acute angle off Kann – before also putting the subsequent rebound just wide.

Atlanta was much improved after the break and striker Josef Martinez came close on numerous occasions. After watching his downward header bounce over the goal in the 51st, the Venezuelan then found himself through on goal just six minutes later only to watch as Rapids goalkeeper Tim Howard came up with a huge deflection before Micheal Azira tracked back to clear off the line.

Howard came up with another fine save in the 65th-minute, denying a spectacular bicycle kick from Martinez. Refusing to be denied again, however, Martinez eventually broke the deadlock in the 67th-minute, collecting the ball just outside the six-yard-box and slotting home to give the hosts the breakthrough.

Deep into extra time, second half substitute Nana Boateng almost leveled things for the Rapids, but his thumping header was saved by Kann just seconds before the final whistle. Mastroeni’s men (5-10-1; 16 points) now set their sights on Tuesday night’s Round of 16 U.S. Open Cup clash at FC Dallas. Kickoff is set for 6:00 p.m. MDT at Toyota Stadium.