Veteran trainer Abel Sanchez has been in the opposite corner against Saul "Canelo" Alvarez on two separate occasions.
Sanchez is the former longtime trainer of middleweight champion Gennadiy Golovkin.
In the first encounter, in 2017, Canelo and Golovkin fought to a controversial twelve round split draw.
The rematch, which took place a year later, saw Canelo win a very close twelve round majority decision to capture the middleweight crown.
Canelo has since become the undisputed champion at the super middleweight limit. And he's captured a world title at light heavyweight, before dropping down to 168.
On May 7th, Canelo will head back up to 175-pounds to challenge WBA world champion Dmitry Bivol.
And the Mexican star is already scheduled to face Golovkin in a trilogy fight in September - with GGG moving up to 168 to take the fight. Golovkin still has to win his middleweight unification in April, with WBA champion Ryota Murata.
Canelo is a heavy favorite to beat both Bivol and Golovkin.
From middleweight to light heavyweight, Sanchez only sees three fighters who can potentially shock Canelo in the ring - Two-time super middleweight champion David Benavidez, unified light heavyweight champion Artur Beterbiev and a properly prepared Golovkin.
At the moment, Sanchez would give those three fighters the best chance of handing Canelo his first career defeat since 2013.
“The only people who can be a tough fight for Canelo are Beterbiev, Benavidez, and a well-trained Golovkin,” said Sanchez to FIghthype.com.
“Those are the only people who can beat Canelo. The ones who walk him down. These are the only ones who can threaten him.”