Only an absence of batting partners denied the tenacious No.7 an 11th Test century on the morning of the second day in the series finale against Australia.
He was stranded on 85 runs from 139 balls when No.11 Lahiru Kumara edged to the slips from Matt Kuhnemann, ending the hosts' innings on 257 early on day two.
By that time, Kusal had played the most prolific innings of any Sri Lankan batter this series as the hosts fight to avoid an ignominious series whitewash on home soil.
"I'm happy with my innings," he said.
"I think I played really well yesterday, with support from Ramesh Mendis and Lahiru Kumara. I hope the second innings I give it my best for my teammates."
Australia went to stumps well ahead of the game at 3-330 - 73 runs ahead of their hosts - but the damage would have been a lot worse if not for Kusal.
Sri Lanka coach Sanath Jayasuriya put his charges on notice for their poor shot selection after collapsing to their worst-ever Test loss in last week's series opener.
But he would have been pleased with what he saw from Kusal.
The No.7 had been gritty late on day one in a seventh-wicket partnership with allrounder Ramesh Mendis, aware that any loose batting would expose Sri Lanka's long tail.
But with the pitch already tricky and primed to become trickier, Kusal got a move on after the resumption on day two.
He brought out the reverse sweep - a shot used by Australia to great effect in their big first Test win, but that Sri Lanka had otherwise struggled to master.
Kusal rode his luck after appearing to edge Nathan Lyon down leg to Alex Carey for what would've been both the final wicket, and the Australian veteran's 550th Test scalp.
Australia reviewed the not-out call and were so confident that Travis Head, Usman Khawaja and Marnus Labuschagne began walking from the pitch.
But there was no spike shown on ultra-edge.
The trio had to walk back from the boundary rope, with Kusal hitting two more fours in the over to pass 80 runs - a first for a Sri Lankan batter this series.
But his innings could've been over before it had properly begun - on medical grounds.
Play stopped just after tea on day one so Kusal and Kuhnemann could undergo a concussion test after colliding on the pitch.
Kusal tried to sneak a single from the non-striker's end but hit the deck bouncing into Kuhnemann, who was rushing to field from his own delivery.
Khawaja checked on Kusal's welfare after he came off second-best, writhing on the ground.
Both men were able to continue and Kusal exacted retribution on the Australian spinners by smacking Lyon for four and then six past deep mid-wicket in consecutive balls.
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