David Williams provided Melbourne Heart’s winner on Sunday for the second straight week in the hottest match in A-League history.

Williams pounced with seven minutes remaining and the scores tied at 1-1 after Patrick Kisnorbo’s 51st-minute header and Terry McFlynn’s close-range equaliser.

With temperatures surging above 40 degrees, and the match already postponed by two hours to avoid the sun’s harshest rays, there was conjecture as to whether the game would even proceed.

The all-important Wet Bulb Globe Temperature measure read 30 degrees at 4pm (AEDT) and had only dropped to 29.4 by 5pm; 1.4 degrees above when the league’s extreme heat policy would have kicked in.

That meant the implementation of two drinks breaks during a subdued first half, when the match began at a glacial pace as players struggled to keep up.

The Heart’s best chance of the opening period came when an errant backpass fell to Harry Kewell some distance from goal, He inexplicably tried to chip the keeper instead of dribbling closer.

His effort left many in the 7000-strong crowd confused.

A drinks break later, Iain Ramsay forced Danny Vukovic into a one-handed save from long distance, with Jonatan Germano’s cheeky near-post effort from the corner also saved.

Jacob Burns provided Perth’s only first-half shot of purpose in injury time, shooting over from Shane Smeltz’s cutback.

On the touchline, Perth coach Kenny Lowe had the look of a man who resented taking his team to Albury, in keeping with his pre-match comments that playing in the heat was avoidable.

Perth seemed to have set out for a 0-0 result but their ambition was crushed after 51 minutes when Kisnorbo soared highest from Mate Dugandzic’s corner.

With the Heart well worthy of their lead, it appeared Glory would spoil their day out in the country in the 73rd minute when a header from a Glory corner was cleared off the line by Aziz Behich, only for McFlynn to pounce and equalise.

But to the relief of the travelling Heart fans, substitute Williams, who scored a last-minute winner against Sydney FC last week, again came up with a late winner for a 2-1 victory.

Played through by Ben Garuccio, Williams had his initial effort saved by Vukovic but scored with a header past the backtracking William Gallas.