Austria's David Gleirscher claimed a surprise Olympic luge gold at the Pyeongchang Games on Sunday after reigning double champion Felix Loch stumbled dramatically with his third successive title in sight.

Gleirscher moved to the top of the standings with a composed final run but German Loch needed only to complete an error-free effort at the Olympic Sliding Centre to be assured of his golden hat-trick.

Having been flawless all weekend, the 28-year-old Loch crashed heavily into the wall early in his run, knocking him completely off medal pace and leaving a disbelieving Gleirscher jumping for joy in the leader's booth.

Gleirscher claimed the title with an aggregate time of three minutes 10.702 seconds, just 0.026 seconds ahead of runner-up American Chris Mazdzer, as snow fell in flurries at the mountainside track.

Germany's Johannes Ludwig won the bronze, with his compatriot Loch finishing a scarcely believable fifth, ending eight years of Olympic dominance, his bid to match compatriot Georg Hackl's 1990s hat-trick in ruins.

On a bone-chilling night at the Olympic Sliding Centre, Loch had grinned at the television camera after grabbing the track record in his third run.

His father Norbert, a former Olympic luger and current head of the German team, clapped his hands and nearly head-butted the ceiling with his jump for joy.

Loch was still beaming in the leader's booth as his rivals took their turns but the smile left his face when American surprise package Mazdzer bettered his time with a scintillating 47.534 run to leap into second.

Mazdzer's camp, consisting of parents, two sisters, his girlfriend and two buddies, all went ballistic at the finish-line terrace, jumping up and down.

The celebrations continued even after he was leapfrogged by Gleirscher, who was competing in his debut Olympics and had never ranked in the top 10 in the last four World Cup seasons.