Substitute Kenneth Vargas scored his first Hearts goal to secure a 1-0 victory over Livingston and ease the pressure on manager Steven Naismith.

The Jambos started the night in the bottom six of the cinch Premiership and, after failing to win any of their previous three matches, they looked set for more frustration until their Costa Rican summer signing stepped off the bench to make their dominance over the Lions count in the 79th minute.

Livingston boss David Martindale – who was the subject of a failed approach from St Johnstone regarding their managerial vacancy earlier this week – was left frustrated as his side suffered a third straight defeat to slip to second-bottom spot.

Naismith made five changes to the side that started Sunday’s agonising 2-1 defeat away to Rangers as Stephen Kingsley, Alan Forrest, Cammy Devlin, Alex Lowry and Liam Boyce replaced Toby Sibbick, Odel Offiah, Jorge Grant, Calem Nieuwenhof and Vargas.

Martindale also rang the changes following Saturday’s 2-0 loss at home to Dundee, with goalkeeper Shamal George, Cristian Montano, Luiyi de Lucas, Dan MacKay, Bruce Anderson and Steven Bradley dropping out to make way for Jack Hamilton, Scott Pittman, Miles Welch-Hayes, Mo Sangare, Andrew Shinnie and Stephen Kelly.

Forrest – playing at wing-back for Hearts – had the first effort of the night from the edge of the box but it lacked the power to trouble former Jambos No.1 Hamilton.

At the other end, Kelly shot over the bar from distance but it would prove to be the Lions’ only notable attempt of a match largely controlled by the hosts.

Captain Lawrence Shankland threatened in the 14th minute when his powerful goal-bound strike from the edge of the box was bravely headed behind for a corner by Lions skipper Mikey Devlin.

The Hearts striker went even closer in the 20th minute when he curled a shot against the crossbar after the ball broke into his path 12 yards out.

The hosts continued to enjoy the majority of the ball but struggled to create clear chances against a well-organised Lions side. Shankland endured more frustration when his ferocious shot from the edge of the box was brilliantly beaten away by Hamilton.

Naismith made a change at half-time as Grant replaced Devlin in a move designed to inject more invention into Hearts’ play.

They continued to probe early in the second period, with Kingsley seeing a strike tipped behind by Hamilton before Lowry shot just over. Shankland then drove another effort agonisingly wide.

The half-chances and near-misses continued for Hearts but, just as it looked like it was not to be their night, Vargas – 10 minutes after entering the fray – stole in at the back post to get on the end of an inviting ball across goal from Grant and fire home from close range.