After impressively controlling the match, Gers just couldn’t take their chances but it is still in their own hands to qualify with a win over Schalke in their final game being enough to take them through.
Gers opened the game with a decent opening for Cammy Palmer with his shot going just wide but it was Atlanta who took the lead on two minutes with Alessandro Castro using the wall for a rebound before netting a decent finish into the far corner.
The Light Blues responded well and drew themselves level within two minutes as after a neat move, the ball broke to Palmer who slewed a neat shot beyond the goalkeeper from just outside the area.
But again, Atlanta fought back, and after making a great initial save, Nicky Hogarth in goal was beaten again for Gers with Will Vint there to net for the MLS side.
Chances came for Dapo Mebude and Jordan Houston before the interval, but both brought out decent stops from the United goalkeeper.
Into the second half, and again, Gers were in control with the bulk of the ball, and Josh McPake came close, shooting just wide after Stephen Kelly took a quick corner.
Time looked to be ticking down on the Glasgow club, but with just over two minutes left, Kelly leveled matters once again after a super combination with Palmer down the left wing.
Twice Mebude had chances to win the game after that with a pair of snapshots, but with the last kick of the game, Atlanta claimed the victory.
Evangelo Spartiatis was able to get a shot away beyond the reach of Hogarth with just seconds to go to bring the Americans back into play in the competition.
With one game to go each, the Group B standings and points are as follows…
With Atlanta facing Bayern in the next game, regardless of the result there, a win for Gers over Schalke will be enough to take them through as one of the top two sides in the group.