Canelo Alvarez has proven himself to be one of the greatest pound-for-pound boxers in the world – and it is going to take a very special athlete to defeat him. However, that hasn't stopped several high-profile names from calling the 31-year-old out.Alvarez is excellent at everything he does in the 'sweet science', and he has been crowned world champion multiple times across an array of weight divisions.He can box opponents who are taller, more powerful, or famously unpredictable in the ring, and even on a bad day, he'll leave with his hand raised.Boxing on BT Sport 🥊@BTSportBoxing2021 Ring Magazine Fighter of the Year, @Canelo 10:56 AM · Dec 30, 202118123042021 Ring Magazine Fighter of the Year, @Canelo 👑🇲🇽🏆 https://t.co/s2Pepu49L5The man – dubbed the greatest of his generation – has faced tough competition in his ascent to the top. And given that he is still looking for his next opponent, we break down five ONE Championship fighters who could box with Alvarez if weight categories weren't part of the stipulation.#5. John LinekerJohn ‘Hands of Stones’ Lineker loves to go toe-to-toe with his rivals in the circle. His aggressive style would also make for a highly-entertaining matchup against the multiple-time boxing world champion.Lineker's fists have powered him to some classic knockouts against top MMA fighters like Kevin Belingon and Troy Worthen over the last couple of years.His left hooks and sledgehammer-like overhand rights are his prized weapons. With 43 fights under his belt, Lineker would bring some experience if he boxed against Alvarez, who has picked up 39 knockouts from 57 wins.ONE Championship@ONEChampionshipListen to the POP of John Lineker’s punches! @johnlineker #WeAreONE #ONEChampionship02:15 AM · Sep 10, 2021768150Listen to the POP of John Lineker’s punches! 🔊 @johnlineker #WeAreONE #ONEChampionship https://t.co/F9HNCdg6baTraditionally, Mexican boxers are known for their ruthless offensive attributes, but Alvarez is not all about the brawl. Despite being known for his offense, the 31-year-old is a very well-rounded boxer.Even on nights where he doesn't seem at his best, the talented pound-for-pound boxer’s ability to stay one step ahead, counter through the smallest of openings, and sting in the latter rounds, often gets him past his rivals.Lineker has fought until the final MMA bell in 19 outings. This record is similar to the boxing star, who has 18 wins by decision and one loss. His only career defeat came from Floyd Mayweather by way of the judges’ scorecard.A boxer’s gas tank is known to be superior to an MMA fighter's, however, so that has to be taken into account. Then again, anything can happen in a fight, so John Lineker vs. Canelo Alvarez would be a good fight for combat sports fans worldwide.