The Earnhardt Ganassi driver was a contender up front for most of the distance, leading for a few laps around halfway though the 500-mile event.
In the closing stages of the race he looked to be in position to threaten leader Kurt Busch as he dramatically closed the gap to the Penske driver until the caution flag waved following Keselowski's Penske Dodge's violent crash after contact with the Roush Fenway Ford of Edwards.
Montoya lamented the timing of the caution as he thought he had a better chance of beating Busch for victory while running a long stint under green and not in a short run following a caution.
"I was within three car lengths [of Busch] just coming to two [laps] to go," said Montoya. "I was, taking three or four tenths a lap [from Busch]. So definitely I thought if I got anywhere close to him, I'm sure I could make a move.
"It's one of those deals. It's okay. It is what is. I told the guys anyway at the end, 'we need to finish, we need the points.' It's a good points day for us."
Montoya said on the final restart he was caught by surprise by Busch, as the Penske driver was quicker off the line. The Colombian believes however that Busch probably restarted before the reference they have on the wall, which marks where drivers can get back up to racing speed.
"We have those two lines we're supposed to restart on," said Montoya. "To be honest, the lines are very short between them. I don't know. I need to ask NASCAR exactly how the rule is. If you're within three car lengths of it or four car lengths of it, can you go? Do you get to really cross the first line, how they're going to police it?
"I'm not saying [Busch] doesn't deserve the win because he did. I was on the outside. I was probably destined to finish second there. When you have the bottom, you can hold it wide open between one and two, you have the bottom in three, you're done."
Montoya has led laps in three out of four races this year but has not enjoyed a good start to his season following an engine failure at Fontana and an incident with his team-mate Jamie McMurray at Las Vegas.
After his third place finish at Atlanta, Montoya now ranks 21st in the standings, exactly the same position he had in the championship a year ago.
Edwards admits crash was deliberateSeason over for Marquez
