Victory for Hibs would have confirmed Hearts' Scottish Premiership fate but goals from Dale Carrick and Billy King at either end of the Tynecastle clash gave administration-hit Hearts the bragging rights.
Locke admitted he had a sleepless night after St Mirren's draw at Inverness on Saturday set up a potential nightmare scenario of Hibs fans celebrating Hearts' relegation at Tynecastle.
Locke added: "I've had hundreds of sleepless nights, to be fair. I'm sick of spending money on Nivea face cream to try to get rid of the wrinkles.
"As I said during the week, it wasn't Hibs that were going to relegate us, it was the fact the 15 points (deduction) had killed us and we hadn't won enough games.
"But obviously it wouldn't have been nice for Hibs to come here and beat us. It would have been a hard one to take.
"It meant a lot to us. It's been a long hard season for us and it was important we gave the fans a result. That result was certainly for them.
"It was very special, being a local lad, that we made sure we won the game. I knew the outcome if we lost.
"The supporters have been through a lot this season and we had to try to repay them."
Hibs struggled to test Hearts goalkeeper Jamie MacDonald despite putting Hearts under more pressure as the game progressed after Carrick fired home in the sixth minute following Ryan Stevenson's knockdown.
But they were denied a legitimate equaliser in the 82nd minute when Jordon Forster was flagged offside as he headed home Lewis Stevenson's cross, despite being two yards on.
Their misery was compounded in the closing minutes when Alan Maybury was shown a second yellow card for bringing down King, who scored an injury-time clincher after being played through by Stevenson.
When asked about a difficult day in the dugout, Hibernian manager Terry Butcher said: "It's made difficult by a decision that's horrendous. The way things are going at the moment, it's par for the course.
"It's so disappointing when a great goal gets chalked off when it's not even close to being offside. We had momentum at that stage, attacking our fans in the second half we felt we could get a goal and go on and win the game.
"I had a few words with the linesman (Alasdair Ross) when we went up the tunnel, but I don't care to repeat them."
However, Butcher admitted his side had lacked a cutting edge.
"We passed it quite well, the system worked really well, but we didn't test the keeper enough," he said. "Jamie MacDonald has not had the most difficult of afternoons.
"We did well up to the final third again but it's the final ball and shots that we don't create.
"It's just having guts and bravery around the box to finish off what the boys have started."
And Butcher admitted concern over his team's form after a run of one win in 13 games, which has seen them become embroiled in the battle to avoid a relegation play-off. Hibs are now only six points above second-bottom St Mirren.
"We need to get more points, it's as simple as that," Butcher said.
"We've had a frank and open discussion between the players and us. We need to pull our fingers out and get points.
"We have gone from being a really difficult team to play against, a team that scores from set plays and grinds out wins, to a team that doesn't score and concedes goals."