Thanks to <hemy> over at <CG> I was able to find the Shachmaty May, 1965 issue with its report on the <Latvian ch, Riga (1965)> tournament held in the spring. Tal used this tournament as a warm-up to his Portisch Candidate’s match in the summer later that year. Tal took first place in the tournament, having to at least draw in his last round game against Roberts Skuja (dob 1910) in order for Tal to finish ahead of Aivars Gipslis, the second place finisher.
(Skuja was lucky to get a draw, see especially around Black’s move 40.)
It turns out that the Shachmaty report features a picture of this game, which was the very last game of the tournament to finish:
Anybody care to guess what move is shown? My guess is just after 12…f6 (eval =/24-ply). See:
As a side note, a word of caution – there was another player, Harijs Skuja who also took part in the tournament.