VIDEO: Arnold Allen's leg kick leaves Calvin Kattar writhing in pain at UFC Fight Night

The recently concluded UFC Fight Night headliner between Calvin Kattar and Arnold Allen ended in anticlimactic fashion. Kattar suffered a fight-ending knee injury in the second round.

Kattar injured his right knee late in the first round when he landed awkwardly after missing a leaping kick. In round two, Kattar immediately realized he could not plant his back leg after absorbing a low kick from Allen. He came crashing onto the canvas: it was evident that something was amiss.

Referee Herb Dean promptly rushed to his aid, stopping the fight just eight seconds into round two.

Watch the finishing sequence of Calvin Kattar vs. Arnold Allen:

Calvin Kattar hurt his knee in the 1st round and Arnold Allen ends it early in the 2nd round with a leg kick. Brutal. https://t.co/sk2cND8zVN

'The Boston Finisher' was noticeably in pain as he held onto his right leg and could not get to his feet.

Dr. David Abbasi, an orthopedic sports surgeon and UFC fan, took to Twitter to render his initial assessment of the injury. According to Abbasi, Kattar's reaction suggested that he may have suffered an anterior cruciate ligament (ACL) tear.

Watch Dr. David Abbasi's assessment of Calvin Kattar's injury:

Calvin Kattar Knee Injury- Knee Surgeon Explains 😷

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#calvinkattar #UFCFightnight #ufc https://t.co/Gwz7axuMiX

However, there hasn't been any official announcement regarding the nature or extent of Kattar's injury. Stay tuned to Sportskeeda MMA for further updates.

Arnold Allen "devastated" despite win over Calvin Kattar

Arnold Allen was hoping to earn a statement win over Calvin Kattar in order to strengthen his case for a title-shot.

However, the unfortunate turn of events denied 'Almighty' the opportunity to do so. During his post-fight interview with Michael Bisping, Allen stated that he obviously wasn't satisfied with how his victory came about. He claimed that he was trying to convince UFC featherweight champ Alexander Volkanovski to give him a title shot:

"I'm devastated, you know. [Alexander] Volkanovski asked the guys to make a statement, but I never [expected] an injury [or] TKO by injury. I can't really ask for a title shot off this. Maybe give me the interim job."

Watch Arnold Allen's post-fight interview below:

Volkanovski made it clear that he intends to move up to lightweight for a potential showdown against newly-crowned champion Islam Makhachev. Their bout is expected to take place in February next year at UFC 284 in Perth, Australia.