Cruz became a two-time Olympic champion following his 5-0 victory, adding a new title after winning at the 2016 Olympics in Rio.
With two more days of boxing left in Tokyo, Cuba has claimed three golds in the sport (before Cruz, welterweight Roniel Iglesias and light heavyweight Arlen Lopez also snagged gold).
Both the Russian and Japanese teams have each won one gold medal. Eight more titles remain to be decided.