Riding bareback and barefoot, the race takes only a minute.
Offering some to our party, a foreign journalist, a linguist and a photographer, we toast to his victory and to the glory of Kopala, and down the beer in as few gulps as possible.
Kochlishvili senior has been presiding over the ritual at Iremtkalo every summer since 1946.
He is the khevisberi, or shrine-priest, more literally, "wise man of the valley".
The three young men, tanked up on sacred beer ("It's technically against the rules to be sober," one of them tells me), gallop off to a semi-ruined shrine almost a mile away.
There, they wait for the signal, and the hundred or so parishioners – vassals of Kopala, the mountain deity – assemble to get a view.
Making incantations under his breath, Kochlishvili rings the bell three times and then clangs it like a fire alarm.
On the third peal the riders take off along the grassy ridge towards the shrine.
On a mountaintop 2,250 metres above sea level in Pshavi, in the Caucasus Mountains of Georgia, Ioseb Kochlishvili is performing a pagan ritual.
Eighty-nine years old, and dressed in a battered suit jacket and corduroys, this is the first year he hasn't walked all the way up here to Iremtkalo, the "meadow of the deer". He leans on his walking stick and steps over the wall into the hallowed ground where only he is pure enough to go.
He approaches a bell tower, a stone structure of about five metres, and rings the bell to tell the riders to get ready.
This year, only three people are taking part in the horse race, but it's still the highlight of the day.