Oleg Korneev vs Sameh Sadek
Golden Cleopatra Open Cairo EGY round 10.2 2016.12.21
French Defense: Tarrasch Variation, Chistyakov Defense 1-0

Olle Algars vs Thomas Ernst
Rilton Cup Stockholm round 1 2006.12.27
Sicilian Defense: Najdorf Variation 0-1

Ollie Willson vs Freja Vangsgaard
Hastings 2016/17 Hastings ENG round 7.33 2017.01.03
English Opening: Agincourt Defense, Keres Defense 0-1

Oluwafemi Balogun vs Yannick Gozzoli
PRO Chess League (Central) chess.com INT round 4 2017.02.01
English Opening: Anglo-Indian Defense, Grünfeld Formation 0-1

Orestes Rodriguez Vargas vs Raymond Keene
Alicante Alicante ESP 1977.01.??
Dutch Defense: Krause Variation 0-1

Orkhan Abdulov vs Jayaram Ashwin
World Junior Championship Gaziantep TUR round 7.28 2008.08.08
Sicilian Defense: Taimanov Variation, Bastrikov Variation 0-1

Oscar Gelbfuhs vs Adolf Anderssen
Vienna Vienna AUH round 11.2 1873.08.26
Italian Game: Evans Gambit 0-1

Oscar Gelbfuhs vs Joseph Henry Blackburne
Vienna Vienna AUH round 4.1 1873.07.31
French Defense: Exchange Variation 1/2-1/2

Oswaldo Zambrana vs Vasilios Kotronias
Bled Olympiad Bled SLO round 9 2002.11.04
Sicilian Defense: Kan Variation, Knight Variation 0-1

P Dosoudil vs Jiri Kuchta
Ch Moravia (open) Prerov (Czech Republic) round 6 1995.??.??
Italian Game: Scotch Gambit, Anderssen Attack 0-1