He timed his run into the six-yard box to perfection to smash home Drey Wright's fiercely driven cross from the right flank.

It was a bitter blow for Livingston, who had hoped to preserve a six-point advantage over Tommy Wright's side, who stretched their unbeaten run to seven games.

Saints' line-up showed five changes from the midweek draw against St Mirren, with Hendry, Matt Butcher, Liam Gordon, Scott Tanser and Jason Holt featuring.

Hard on the heels of their draw with Celtic, Livingston freshened up with Nicky Devlin, Jack McMillan and Marvin Bartley all getting starts.

Lions defender Efe Ambrose lined up a tempting 25-yard free-kick in the eighth minute after a Gordon handball, but the Nigeria international's weak effort was aimed straight at the defensive wall.

Saints came close in the 17th minute when Jason Kerr's cross was glanced goalwards by striker Stevie May, forcing keeper Robbie McCrorie to instinctively beat out his header.

But Perth goalkeeper Zander Clark produced an even more impressive stop seven minutes later to spare the blushes of errant defender Gordon. The centre-half's fluffed back header was pounced upon by Steven Lawless and his dipping 25-yarder was tipped over the bar by the backtracking Clark.

On the half-hour mark, Livi skipper Bartley sensed an opportunity at the back post but Gordon redeemed himself with a vital block at the expense of a corner.

Lawless had another chance in the 34th minute when he latched onto Bartley's prod into the penalty area. This time the attacker's angled shot eased wide of the far post.

Time-wasting earned needless cautions for rivals Craig Sibbald and Hendry, with Jack McMillan joining them for a hefty challenge.

Saints keeper Clark raced from his area nine minutes after the break in a sprint against Lyndon Dykes, but he had to improvise a header into touch after losing his footing.

Well-drilled Livi looked happy to settle for a point as the second half panned out but they were undone by Hendry's 84th-minute side-footed finish, which lifts Saints into seventh place, just one point behind Hibernian.