Watch: John Lineker Ends Michael McDonald's Comeback Tour with Vicious KO

Michael McDonald was once the next big thing in MMA. A long, strong, and incredibly young bantamweight, he won the Tachi Palace Fights bantamweight title at just 20 years old, made his way to the UFC not long after and earned himself a title shot shortly thereafter by beating respected veterans Chris Cariaso and Miguel Torres.

The good times ended there for McDonald.

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McDonald has been struggling ever since losing to Renan Barao in 2013.

Then-champion Renan Barao handily defeated him at UFC on Fuel TV 7, and Urijah Faber dominated him not long after. Then he suffered a series of injuries.

Two years passed and McDonald returned to a radically different bantamweight division. When he left, it was largely comprised of WEC holdovers like Takeya Mizugaki, Scott Jorgensen and Brad Pickett. When he returned, the top-10 was almost entirely made up of a newer, better bred 135-pound fighter.

While his first fight back was a come-from-behind submission win over Masanori Kanehara, one serious question still lingered: How does Michael McDonald stack up against today's breed of bantamweight?

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McDonald had a tough draw in Lineker.

At UFC Fight Night 91, where he faced John Lineker, the answer proved to be "not especially well."

From the first bell, the effects of Lineker's power punching were felt. The normally aggressive McDonald was on his bicycle, working from along the periphery of the cage, relegated to using little more than a fadeaway jab. Eventually, however, Lineker found his opening and exploded into it.

A right-hand liver shot was followed by a clean left hook to the chin, which sent McDonald crashing to the canvas. Lineker chased him to the mat with ground-and-pound, but McDonald managed to escape...for a time. Another brutal left hand would land with a series of uppercuts behind it, leaving McDonald limp and thoroughly, deeply unconscious. 

BOOM! John Lineker brings the thunder with a huge knockout win over Michael McDonald! #UFCSiouxFalls https://t.co/r4zcyr5LHM

— FOX Sports: UFC (@UFCONFOX) July 14, 2016

The fight was waved off at 2:43 of the first round, sending many into a state of introspection.

It's not an especially surprising outcome. Lineker has established himself as one of the pound-for-pound best power punchers in MMA today, earning 13 knockout wins and topping that with more than a few strike-induced submissions on top of it. He has starched a number of solid names and very easily could have fought for the UFC flyweight title if he didn't have consistent trouble cutting down to the 125-pound limit.

Despite the fact there is no shame in being floored by Lineker's punches, this leads to an unflattering audit of McDonald's overall abilities.

"Dominick Cruz, I'm coming for you baby!" That was the most charming and threatening call-out I've heard recently. #UFCSiouxFalls

— Dr. Patrick Wyman (@Patrick_Wyman) July 14, 2016

McDonald owned a substantial size advantage over Lineker—standing five inches taller—and had plenty of tape to work with on his relatively predictable foe. Still, Lineker managed to get inside McDonald's guard repeatedly, had no real trouble implementing his "press forward, throw shots to the body and follow up with headshots" game plan.

It's a win for Lineker that could easily line him up for a title shot. With fighters like Raphael Assuncao, Urijah Faber and Aljamain Sterling all coming off tough losses, Lineker stood tall here and could be just one win away from earning a crack at the belt.

McDonald, on the other hand, finds himself in rebuilding mode. That's not necessarily a bad place for an immensely talented 24-year-old, of course. Fighters like Robbie Lawler and Rafael Dos Anjos have both weathered far more dire straits and exited with UFC gold. He remains a young, high-upside prospect who can endure in the division for years to come and could easily challenge for the bantamweight title some day.

Not today, however. Today belongs to John Lineker.