"Ryan Stevenson looked up and saw David running into the box and he met it perfectly. It gave him a lift, he was better after that.
"I'm happy with the result because that's the most important thing."
Obua's goal came just after Hearts goalkeeper Marian Kello had prevented Flavio Paixao giving Hamilton the lead and the stopper made another block to foil Brian Easton's volley late in the game.
"It was all about the first goal; who was going to get it was probably going to go on to win," said Jefferies.
"Fortunately he made a great save and we got the goal at the other end.
"And then the save after that when it's rifled at him, you couldn't blame him for dropping it, but the reaction to gobble it up was terrific goalkeeping."
Laryea Kingston came off the bench to make his first Hearts appearance since December and Jefferies was glad to see his playmaker back in action.
"Laryea Kingston, I thought for the 15 minutes he got on, was lively," added Jefferies.
"He got in the game and had a few efforts on the goal."
Source: BBC Sport