Claressa Shields has won the United States' only boxing gold medal with an impressive 19-12 victory over Russia's Nadezda Torlopova.

There was not much in terms of movement, as the pair stood in front of each other winding up with big punches.

Torlopova scored well with single shots, but the American put together a decent combination to end the round level on 3-3.

Shields found her rhythm in the second round and was beginning to land with greater accuracy and volume.

The Russian was struggling to cope with Shields's explosive speed when she unleashed her attacks and fell behind 15-10 after three rounds.

The American continued to march forward in the final stanza, but still Torlopova could not land a punch.

Shields went on to wrap up a 19-12 victory and the middleweight gold medal.