Striker Eli Babalj netted the only goal of the game as Heart moved above Newcastle into fifth place.
Striker Eli Babalj netted the only goal of the game in the 50th minute with the victory moving the Heart above Newcastle into fifth place and three points clear of Sydney in seventh.
English import John Sutton spurned a glorious chance to equalise when his penalty hit the post leaving the Mariners just three points clear of Brisbane Roar at the top of the table.
Heart regained two of their Olyroos representatives with Aziz Behich and Mate Dugandzic rushed straight back into the starting XI.
The Mariners welcomed back Matthew Ryan in goal, but were without midfield dynamo Mustafa Amini, who was rested.
In a cagey opening neither side gave much away with referee Jarred Gillett the busiest person on the pitch, dishing out four yellows in the first 15 minutes.
Tomas Rogic had the first two genuine chances but both of his strikes from outside the area were hit straight at Bolton.
Adam Kwasnik almost found the back of the net with a great header from Pedj Bojic cross, but it flashed just wide of the post.
Heart captain Fred had his side's only real chance on goal, but his curling effort from outside the box was never going to trouble Ryan.
The match came to life in the 50th minute when Babalj broke the deadlock with a smart finish from close range.
Dugandzic charged down the right flank and found Fred unmarked on the edge of the area and his scuffed shot was trapped by Babalj, who beat Mariners defender Alex Wilkinson to the loose ball and found the back of the net.
With their tails up, Heart almost had a second minutes later but Behich’s curling effort flashed just wide of the post.
Up the other end, the Mariners had the perfect chance to equalise when Rogic was clumsily brought down by Fred in the area.
Debutant Sutton stepped up to take the spot kick but his effort crashed straight into the upright and Clint Bolton was then relieved when Patrick Zwaanswijk’s follow up lacked power with the goal at his mercy.
Graham Arnold replaced Sutton with Bernie Ibini and the youngster had an immediate impact with two shots in the space of a minute, but neither troubled Bolton.
Babalj had a glorious chance to put the game to bed in the 76th minute but after finding space in the area he blasted his shot over the bar.
The Mariners threw everything at the hosts in the closing stages but never really threatened Bolton’s goal as the Heart held on for a valuable three points.