Nonito Donaire was crowned WBA super world bantamweight champion and moved into the semi-finals of the World Boxing Super Series when Ryan Burnett retired due to a freak injury in Glasgow.

Burnett lost his unbeaten record in bizarre fashion at The SSE Hydro, damaging his back when he missed with a right hand in the fourth round.

The Northern Irishman dropped to his knee in the ring holding his back and was peppered by the 35-year-old Donaire on the ropes after returning to his feet. 

Burnett's team called an end to the fight after he returned to his corner at the end of round four, bringing an anticlimactic end to a bout which had promised so much in the early rounds.

Former four-weight world champion Donaire, dropping down from featherweight to fight in the bantamweight for the first time in seven years, showed great sportsmanship to check on a shell-shocked Burnett after dethroning him in such strange circumstances.

Donaire, nicknamed the Filipino Flash, will face South African Zolani Tete in the last four, while Burnett was carried out of the ring on a stretcher in agony with concerns over the extent of the damage done.

Burnett had caught troubled Donaire with fast hands in a high-tempo start, but the veteran showed his class as he pinned the Belfast native back, catching him with sharp combinations in the second round.

Donaire was on the front foot in the third, but Burnett continued to come forward in a contest which was bubbling up nicely until being so cruelly cut short.

Josh Taylor later sealed his place in the super-lightweight semi-finals with a seventh-round stoppage of Ryan Martin in his homeland.

Taylor improved his unbeaten record to 14-0 and will get a chance to claim Ivan Baranchyk's IBF title after consigning Martin to the first defeat of his career, having floored the American with a left hand to the head and one to the body.