Complex sentence: On January 4, Okada defeated Yoshi-Hashi in his return match and then challenged Hiroshi Tanahashi to a match for the IWGP Heavyweight Championship.
Split into simpler sentences: On January 4, Okada defeated Yoshi-Hashi in his return match. After the main event of the evening, Okada challenged Hiroshi Tanahashi to a match for the IWGP Heavyweight Championship.