Callum Smith can beat Saul 'Canelo' Alvarez if deal is struck, says Liam Smith
Britain's WBA world super-middleweight champion Callum Smith can "upset the world" if he fights Saul 'Canelo' Alvarez, says his brother and former world champion Liam Smith.
Callum Smith, 29, has said he is "game" for fighting Mexico's Alvarez, who holds three middleweight world titles.
Liam Smith, 30, lost his light-middleweight world title to Alvarez, 28, in 2016.
He told BBC Sport: "I think if anyone beats Canelo, it's Callum Smith."
He believes the natural size advantage his 6ft 3in brother has over Alvarez, who is 5ft 8in, would prove crucial should the two meet.
Alvarez - the world's best-paid fighter - could complete a trio of bouts with Gennady Golovkin by facing him next, but his team have also indicated they would like to set up a fight with Callum Smith.
"It's so good to pit your wits against someone like that," said Liam Smith, who was stopped in the ninth round by Alvarez.
"Canelo is class, but that is not the be all and end all. Callum is bigger, can box, fight and can dig in. I would be massively confident in him going into that fight and believe he could upset the world."
'Callum the best of the Smiths'
Callum is the youngest of four Smith brothers, all of whom have held British titles and fought for world honours.
He won his world title by beating George Groves in September and retained it in clinical fashion against Hassan N'Dam earlier this month.
"Callum has given us all inspiration," said Liam Smith, who expects to fight next in July or August.
"He is so calm and we all played a part in that. Every stage he has come to, he had been there before with one of his brothers.
"Paul fought for a world title, then Stephen did and had seen Paul do it. Then I challenged for a world title and had seen Paul and Stephen do it. Now, with Callum, he probably feels he has seen it all.
"We told people for years how good he was. People maybe thought we were talking up our younger brother. We were not telling lies, he was the best out of us and is slowly but surely proving that."
'Legacy or loss - Canelo will risk it'
Alvarez has six brothers who boxed at a professional level but none have come close to matching his record of 52 wins, two draws and a single defeat - at the hands of Floyd Mayweather in 2013.
He has held full versions of world titles at light-middleweight and middleweight and, such is his status in the sport, signed a record-breaking fight deal in October worth a reported £278m.
Victory over Britain's Rocky Fielding in December brought him a version of a world title at super-middleweight.
Liam Smith believes Alvarez learned little about life at 168lbs with three rounds opposite Fielding, but fully expects him to face his brother.
"I think he is young enough and that he likes a challenge," said Liam.
"Canelo knows if he beats Callum he leaves a better legacy but if he struggles and does have his doubts when facing a bigger man then a loss potentially ruins a bit of his reputation.
"It will be a big ask and risk for Canelo but he likes a challenge, and if he wins his next fight he will test himself."