Amir Khan knocked out cold by Canelo Alvarez; British boxer stopped in Round 6; Alvarez shows concern for Khan after huge knock out <br /> Canelo Alvarez knocks out Amir Khan <br />Saul 'Canelo' Alvarez stands over a floored Amir Khan after unleashing a quite brutal <br />Canelo Alvarez, left, watches after knocking down Amir Khan
