WBO middleweight champion Billy Joe Saunders has issued a challenge to Gennady Golovkin for a unification title fight between the duo.

Golovkin defended his WBC, IBF, WBA and IBO middleweight titles against Canelo Alvarez by way of Saturday night's (16 September) split-decision draw in Las Vegas.

Meanwhile, Saunders defended his WBO middleweight title earlier in the day after his unanimous decision win over Willie Monroe Jr. at the Copper Box Arena in London.

Following his win, Saunders challenged "GGG" to a title fight where the winner would hold all the middleweight titles, resulting in a true unified champion.

"Weekend is out the way, back to good food today, back in camp next week," Saunders tweeted after his win.

"Golovkin, well done champ for Saturday. Are you ready? Because I am. All the belts!"

Saunders has wanted to face the 35-year-old for a while, having previously claimed that he can beat Golovkin.

A fight with Golovkin is not out of the picture either as while most would assume there will be a rematch with Canelo, the Mexican stated his need to take some time off, predicting a return in 2018 in May or September.

This opens up the possibility of a bout in December as Saunders' promoter Frank Warren hopes the 28-year-old's next opponent will be the Kazakhstan boxer.

"He [Saunders] will fight in December," Warren told iFL, as quoted on The Sun. "We'll have him out again in December, hopefully it's Golovkin."

A middleweight contest between the pair is unlikely to be as big or successful as Golovkin-Canelo, however, no boxer has held all four major middleweight titles since Jermain Taylor accomplished the feat in 2005 after his win over Bernard Hopkins.

Billy Joe Saunders
Saunders defeated Monroe Jr a couple of hours before Golovkin's split-decision draw with CaneloGetty