Scotland's Josh Taylor used a relentless attack and two knockdowns to become the undisputed junior welterweight champion with a unanimous decision victory over Jose Ramirez on Saturday in Las Vegas.

Both former Olympic boxers came into the fight unbeaten and holding two belts but Taylor made sure he was the one to leave with all four 140-pound straps.

The 30-year old Taylor defended his World Boxing Association and International Boxing Federation titles and captured Ramirez's World Boxing Council and World Boxing Organization belts at the Virgin Hotel.

Scotland's Josh Taylor celebrates his win by unanimous decision over Jose Ramirez in their junior welterweight world unification title fight at Virgin Hotels Las Vegas
Scotland's Josh Taylor celebrates his win by unanimous decision over Jose Ramirez in their junior welterweight world unification title fight at Virgin Hotels Las Vegas GETTY IMAGES NORTH AMERICA / David Becker

"I've trained for this all my life," Taylor said.

Taylor won by 114-112 scores on all three judges' cards to improve to 18-0 with 13 KOs.

Ramirez suffered the first loss of his long career, with the Mexican-American falling to 26-1 with 17 KOs.

Taylor floored Ramirez in back-to-back rounds in the middle of the fight.

Taylor floored Ramirez in back-to-back rounds in the middle of the fight
Taylor floored Ramirez in back-to-back rounds in the middle of the fight GETTY IMAGES / David Becker

He landed a left on the chin in the sixth to knock Ramirez down and then did it again in the seventh with a short uppercut.

Taylor is now just the sixth four-belt champion in boxing history and Scotland's first undisputed champ since the great Ken Buchanan unified the lightweight division by winning the WBA, WBC and lineal championships in the 1970s.

"I am so determined to win. My will to win is second to none," said Taylor.

Taylor beat Ivan Baranchyk to win the IBF title in May 2019 before beating Regis Prograis to earn the WBA belt.

Taylor won by 114-112 scores on all three judges' cards to improve to 18-0 with 13 KOs
Taylor won by 114-112 scores on all three judges' cards to improve to 18-0 with 13 KOs GETTY IMAGES / David Becker

Ramirez actually got the better of Taylor in the opening rounds and was the busier of the two in the 12th, but he couldn't overcome the two knockdowns which seemed to sap him of his power and allowed Taylor to compile extra points on the scorecards.

Ramirez hurt Taylor in the third round using a combination of head and body shots.

Taylor tried to clinch but Ramirez swarmed him for much of the round, trying not to let his opponent catch his breath.

In the fourth, Ramirez kept up the attack and was able to easily break through Taylor's defence and land some hard body shots.

But the fight turned early in the sixth round when southpaw Taylor displayed not only his power but his relentless attack, hitting Ramirez with a brutal left counterpunch directly on the chin that sent the American to the canvas.

The second knockdown came one round later as Taylor unleashed a short uppercut from in tight that Ramirez never saw coming. Ramirez hung on and was saved by the bell.

The two knockdowns took a heavy toll on Ramirez, who has never scored a knockdown over an opponent past the sixth round in his career.

At that point Ramirez's corner became concerned and tried to motivate the fighter by saying "this is for all of Mexico. Do this for your family."

Both fighters landed good punches in the tenth round. Taylor, figuring he had done enough earlier in the fight to win it on the scorecards, was content to backpedal and clinch in the final round.

Ramirez, an American citizen, has long been an advocate for Latino farm workers in California's Central Valley.

He started his title run in 2018, beating Amir Imam to win the WBC title. He became a unified champion in 2019 when he stopped Maurice Hooker in Texas to win the WBO belt.