Jamie Paterson and Simon Cox also scored in a workmanlike display as Forest stretched their unbeaten run to 13 matches, with Kieffer Moore replying for the Glovers.
"It was a great goal, a striker's goal - off his bum, off his hand and into the back of the net from a couple of yards," said Kelly.
"I'm really pleased for him. He'll get better when he gets to know everybody and gets fitter.
"He's a goalscorer, a goal poacher and it's very early days for him."
Forest started off like an express train, with Henri Lansbury curling wide and Paterson's shot being blocked inside the first three minutes, but sloppy defending at the back almost led to a surprise Yeovil opener, but Moore shot wide.
Sixteen minutes in, though, Forest took the lead as Paterson latched on to Lansbury's through ball and his effort was helped in by Byron Webster.
Yeovil hit back to equalise 10 minutes later, with Moore beating keeper Karl Darlow to Jamie McAllister's cross to head into an empty net.
But seven minutes before the break, midweek scoring hero Cox found the target again to restore Forest's lead. Paterson's effort was parried by Marek Stech to Mackie, who crossed for Cox to stab home.
After the break, Lansbury had a shot saved by Stech and Paterson fired against a post in a couple of rare chances as both sides struggled to create much going forward.
And after McAllister went close to grabbing a late equaliser, it was left to second-half substitute Djebbour to bundle home Cox's driven effort to seal the points.
Kelly admitted he was pleased with the result, but played down talk of automatic promotion as they moved to within six points of second-placed QPR.
"It was a brilliant result and we're delighted to have come through a difficult game," said Kelly.
"We created quite a few chances, especially in the first 10-15 minutes and I thought we should have been further away.
"We're not talking about promotion, we really are taking it one game at a time and our biggest focus now is Preston on Wednesday in the FA Cup."
Yeovil boss Gary Johnson was left to reflect on a second defeat in the East Midlands in a week that left the Glovers rooted to the foot of the table.
He said: "Nobody likes losing matches, but we have to be realistic. We started poorly and gave away a soft goal. It took us a while to get going, but once we started passing it I thought we had them worried.
"In the second half we had a couple of chances and until they got their third goal I thought we had them on the ropes at 2-1 down."
The Glovers are now six points away from safety and Johnson added: "We've definitely not given up and heads will not drop just yet. All we've got to do is keep learning and the boys have got to believe in themselves."
Asked if he thought Forest were promotion material, he said: "Yes I do. They've just got that extra bit of quality and players to win games and that's what we've found with prospective Premier League teams."