OpenAI's o3.4 mini has emerged victorious at the Kaggle Game Arena chess tournament, which concluded on August 7, 2025. The AI model achieved a flawless run, remaining undefeated throughout the prestigious event. In the final match, o3.4 mini decisively defeated xAI's Grok 4. Google's Gemini 2.5 Flash secured the third-place position, earning the bronze medal.
The tournament utilized a round-robin format, ensuring all participating AI models competed against each other. During the semifinals, OpenAI's o3 model demonstrated a commanding 4-0 victory over its counterpart, o4-mini. In contrast, the semifinal match between xAI's Grok 4 and Google's Gemini 2.5 Pro was a close contest, decided by a tiebreaker. Observers noted that Grok 4's performance in the final against o3.4 mini was significantly weaker than its earlier matches, with multiple tactical errors, including repeated queen losses. Grandmaster Hikaru Nakamura, providing live commentary, observed Grok 4's numerous mistakes while highlighting the precision of OpenAI's model. Elon Musk, founder of xAI, stated that the company had invested minimal effort into chess for Grok, suggesting its performance was an emergent capability. The Kaggle Game Arena plans to host regular events, expanding to other strategic games to further assess AI development and performance benchmarks.