World Boxing Association middleweight world champion Gennady ­Golovkin stopped Mexico's Marco Antonio Rubio in the second round on Saturday (US time) in Los Angeles, California to keep his title, taking his 18th consecutive knockout triumph in emphatic fashion.

The unbeaten 32-year-old from ­Kazakhstan, a 2004 Olympic silver medalist, improved to 31-0 with 28 knockouts, the latest coming 79 seconds into the second round and extending a streak of victories inside the distance that began in 2008.