"Don't f**k with Australia" - Jake Paul, Manny Pacquiao, and more react to George Kambosos Jr.'s upset win over Teofimo Lopez

George Kambosos Jr. upsets Teofimo Lopez [Photos via @ESPNRingside on Twitter]

George Kambosos Jr. has pulled off one of boxing’s greatest upsets in recent memory after outduelling rising superstar Teofimo Lopez.

The fighting pride of Australia edged Lopez via split decision (115-11, 115-113, 113-114) to become the IBF, WBO, WBA, and The Ring lightweight world champion.

KAMBOSOS DROPS TEÓFIMO 🔥

#LópezKambososJr https://t.co/8c0dNuMbHi

Kambosos came at Lopez from the get-go, dropping the champ with a looping right hand. Lopez returned the favor in the 10th round as he secured a knockdown of his own, but Kambosos quickly recovered and finished strong.

A KNOCKDOWN FOR TEOFIMO LOPEZ. #LopezKambososJr https://t.co/YMp2TXjtXy

Lopez was not too pleased with the decision. The American did his best Kanye West impersonation, interrupting his opponent's post-fight interview in protest of the result.

Nonetheless, Kambosos shattered all odds despite being continuously overlooked and handed Lopez his first defeat. Here's how some of the biggest names in combat sports reacted to Lopez vs. Kambosos.

Boxing stars react to Teofimo Lopez vs. George Kambosos Jr.

Boxing legend Manny Pacquiao congratulated his training partner George Kambosos on his monumental win. Over the course of three years, Kambosos was the chief sparring partner for Pacquiao.

During their time together, the pair reportedly sparred for roughly 250 rounds. Kambosos' training sessions with the Filipino icon paid off in a big way as he's now an undisputed champion. Of course, Pacquiao was one of the first people to extend his congratulatory regards.

Congratulations to my friend, @georgekambosos, on an epic win! You helped me in so many of my past fights, I hope our hundreds of rounds of sparring helped you in some way tonight. I’m proud of you. #LopezKambosos

YouTube star-turned-professional boxer Jake Paul was ecstatic to see Kambosos pull off the upset. Paul took to Twitter to congratulate Kambosos and the entire country of Australia.

DONT FUCK WITH AUSTRALIA🇦🇺

CONGRATS @georgekambosos

#LopezKambososJr

Meanwhile, boxing world champ and MMA fighter Claressa Shields said she didn't expect such a flat performance out of Teofimo Lopez. Just the same, Shields celebrated Kambosos' win and welcomed him to the "undisputed club."

Didn’t expect this twitter.com/kcboxtrainer/s…

Welcome to the undisputed club @georgekambosos 🎉!

Meanwhile, boxing trainer and fight commentator Teddy Atlas believes Lopez and his corner still have a lot to learn after tonight's defeat. He compared the new champ to Italian-Canadian legend Arturo Gatti.

Lopez has lot to learn, and his father also, starting with u need to do more than curse in corner. #LopezKambosos #DAZN

Kambosos reminds u of Arturo Gatti the way he gets hurt and comes back. Incredible fight. #LopezKambosos #DAZN

UFC stars react to Teofimo Lopez vs. George Kambosos Jr.

UFC featherweight champion Alexander Volkanovski was thrilled to see his fellow Aussie bring home the gold. Volkanovski took to Twitter to celebrate his compatriot's victory.

How good!!🇦🇺 #LopezKambosos twitter.com/sportsbetcomau…

Meanwhile, UFC bantamweight champion Aljamain Sterling admitted he didn't know who Kambosos was prior to the fight. Nevertheless, after the Australian's performance against Lopez, it's safe to assume that Sterling won't ever forget who he is.

No clue who this Kambosos guy is but he’s fighting very well and I’m completely shocked by this performance. Hoping Lopez can turn it up these last 5 RDs! #LopezKambososJr

Combat sports journalists react to Teofimo Lopez vs. George Kambosos Jr.

Marc Raimondi of ESPN and Luke Thomas of CBS Sports were both disappointed with Teofimo Lopez's performance. Raimondi believes Lopez "underperformed" while Thomas thinks Lopez looked "unrecognizable".

Lopez is underpeforming, but this fight with Kambosos is damn fun. #LopezKambososJr

The Lopez who fought Lomachenko is unrecognizable relative to the one tonight. Kambosos is very likely winning this fight and Lopez seems to have no adjustments.