zydeco: Keres' notes on this game are pretty interesting. He says he usually played 7....b6 but tried 7.....dxc4 to change it up in a game he had to win.
9.Qd3 is fairly standard but really only has purpose if black exchanges on d4. Keres thinks white's best is 9.Qe2.
Keres suggests 10.a3 Ba5 11.dxc5 Nxc5 12.Qxd8 Bxd8 with a slight pull for white in the endgame.
Keres thinks 12.Bc2 was imprecise (better 12.Bd2).
By move 12, Keres already feels that he has the initiative. The next few moves are all about jockeying for e4. White can't play 13.e4 because of 13.....cxd4 14.Qxd4 Bc5. After 13.Na2 white is threatening 14.e4 and 13....Ba5 14.e4 cxd4 would walk into 15.b4, so Keres improves with 13....a5. With 17.dxc5, white was finally ready for 18.e4 (after 17....bxc5) so Keres instead sacrifices a pawn.
Keres' idea is 17.cxb6? Qc5! threatening 18....Bd5 and 18....exf3. If 18.Ng5 Ne5 19.cxb6 Qc5 with compensation for the pawn.....but this is probably what Gligoric should have played. I've noticed that in a few of Gligoric's games (like Petrosian-Gligoric from the same tournament), Gligoric has a tendency to unnecessarily give up material, as he does with 18.c6, rather than trying to defend with a material advantage.
20.g3 was Gligoric's last real chance to hold out.
22.Nxc6 runs into 22.....Nf3.
Keres sometimes has trouble with last-round, must-win games, but here he overcomes a case of flu to win very smoothly.