Dating back to 1947 during his days in as an undergraduate student at Odessa University when he entered into big time chess in the Odessa Team Championship, one could predict that he would go far.
His very first tournanment games were marked by inspired, attacking chess. He studied the games of Chigorin, Alekhine, Botvinnik and Smyslov and searched diligently for theoretical improvements. He improved rapidly and in 1949 he finished first in the semi-final of the USSR Championship and was awarded the coveted Soviet Master title. In his first international tournament in Budapest 1952, he finished second behind Paul Keres but ahead of the world champion Botvinnik, Petrosian and Smyslov. As a result he was awarded the GM title.
The year 1955 saw him tying for first with Smyslov in the USSR Championship and then by defeating Smyslov 4-3 in the playoff, Geller established himself as on of the world's elite. Over the next 25 years, he was to be a regular qualifier for the world championship candidates cycles. In the 1953 candidates, he finished sixth and shared third in 1956. His best result came in 1962, when he shared second place with Paul Keres.
Take a gander at his record against the world's leading players: Mikhail Botvinnik (+4 -1 =7), David Bronstein (+5 -4 =12), Tigran Petrosian, (+5 -3 =32), Vasily Smyslov (+11 -8 =37).
Against Mikhail Tal his record was +6 -6 =23. He had a minus one score against Paul Keres (36 games), Bent Larsen (11 games) and Mark Taimanov (30 games). The only players against whom he did not fare well were Viktor Korchnoi (minus 5), Boris Spassky (minus 4) and Lajos Portisch (minus 2). Among his most interesting encounters were those against Bobby Fischer. Geller scored 5 wins, three losses and only two were drawn.
At Skopje, 1967 Fischer lost his third game in a row to Geller in the following miniature prompting Yugoslav GM Bojan Kurajica to write that Fischer just couldn't play against Geller. Another Yugoslav, GM and journalist Dr. Petar Trifunovic, opined that Geller was in no way inferior to Fischer when it came to opening preparation and Fischer chose to play sharp opening variations because he was always playing to win. In this game Fischer succeeded in outplaying Geller in the opening, but his play was tactically flawed and Geller, who was a superb tactician, was quick to take advantage of it.
Skopje 1967 was the first in a series of international tournaments and featured a field of 18 players: twelve Yugoslav masters, plus Peter Dely (Hungary), Luben Popov (Bulgaria) and Bela Soos (Romania), two Soviet players, Efim Geller and Ratmir Kholmov, and Bobby Fischer rounded out the field.
Fischer had just recently come out of hiding and this was an important warm-up for is participation in the Sousse Interzonal later in the year. As it turned out, Sousse was to become famous because of the Fischer Affair. The tournament schedule was modified to fit Fischer and Reshevsky's religious obligations. See my post Bobby Fischer and the World Wide Church of God. After a dispute with the organizers over scheduling the games, Fischer walked out while he was leading.
At Skopje it appeared that Fischer might find the going tough because Yugoslav GM Milan Matulovic, Geller and Kholmov had plus scores against him. The tournament was also a precursor of what was to come at Sousse.
Fischer had lost his second round game to Geller and after nine rounds he was tied for first with Kholmov. It was at that point that Fischer once again revealed himself to be the loathsome snot face he really was. He announced he would withdraw from the tournament unless the chess sets were modified and the spectators removed from further rounds. The organizers could not meet the second demand so Fischer forfeited his tenth round game against Yugoslav master Milorad Knezevic (October 31, 1936 - March 31, 2005 ), who was later to become a GM in 1976. Knezevic showed he was quite a sportsman when he didn't want to accept a free point and allowed the game to be re-scheduled for the next rest day; it ended up drawn.
After that, Fischer found his form, defeated both Matulovic and Kholmov and went on to finish first by a half point ahead of Geller and Matulovic who tied for second. Kholmov was a distant 4th.
Besides his loss to Geller given here, Fischer lost to Dragoljub Janosevic who tied for 13th and 14th place. Geller was undefeated and beat both Fischer and Matulovic but had too many draws against players in the middle and lower half of the standings. Matulovic's only two losses were to Fischer and Geller.
Although the following game is a miniature loss by Fischer, looking at it with Stockfish shows it to be enormously complicated and had it not been for Fischer's blunder he likely would have won. Fischer blamed the loss on 20.a3. It was a mistake, but the actual losing move came on his next move. But, it's hard to be hard on Fischer because the position was very, very complicated.