Hong Kong phenom Rex Tso Sing-yu was burning the midnight oil as he ran hot again to continue his amazing win streak to 21 victories after knocking out Japanese Hirofumi Mukai on Saturday night. Tso entered the ring to a raucous welcome by 8,000 fans who waited the whole night to see him in action and he didn’t disappoint as he scored two knockdowns before delivering his payload and ending the fight 32 seconds into the eighth round with a devastating left hand to Mukai’s abdomen.