It was a successful homecoming for 10th-ranked welterweight Santiago Ponzinibbio as he defeated Neil Magny by fourth-round knockout in the main event of UFC Argentina. Ponzinibbio, who was born in La Plata, Argentina, has now won seven fights in a row. For Magny, who was ranked eighth in the welterweight division, this loss snaps a two-fight win streak.

Ponzinibbio opened the fight by taking control of the center of the octagon and forcing Magny to back up against the cage. He hurt Magny with a jab that went straight into his right eye. Magny couldn't get anything going thanks to Ponzinibbio's intense pressure. Ponzinibbio landed a huge right hand towards the end of the round. Magny came out in round two with more activity and was able to land some shots, but Ponzinibbio continued his forward pressure and knocked him down twice with leg kicks. The referee stopped the fight briefly to check on a cut over Ponzinibbio's eye that was caused by a headbutt. When the fight restarted, Ponzinibbio landed another huge leg kick that floored Magny, who was having trouble with his movement. Ponzinibbio landed another hard left hand that hurt Magny as the round ended.

Magny landed a jab and a leg kick at the start of round three and clearly was moving with more urgency, but he ended up back to the fence because of Ponzinibbio's pressure. Ponzinibbio landed another leg kick that caused Magny to visibly limp and lean on the fence to stay upright. Magny showed a lot of toughness and worked his way off the fence multiple times despite his movement being compromised. Ponzinibbio kept up the pressure but looked to be slowing down a bit as he threw less punches. Magny landed more in the round, but Ponzinibbio landed the harder shots. Ponzinibbio scored another knockdown with a leg kick at the start of the fourth round. He did it again, but he never followed Magny to the ground and forced him to stand back up each time. After standing back up following another brutal leg kick, Magny was clearly in trouble. Ponzinibbio landed another leg kick and followed up with a right hand that caused Magny to faceplant into the mat.

It was the first fight in nearly a year for Ponzinibbio following a knee injury. In his post-fight interview, Ponzinibbio said he plans on earning a title shot in 2019 and he called out welterweight champion Tyron Woodley.

Full results from the event can be found below:

- Santiago Ponzinibbio def. Neil Magny via KO (punches) at 2:36 of Round 4

- Ricardo Lamas def. Darren Elkins via TKO (punches) at 4:09 of Round 3

- Johnny Walker def. Khalil Rountree Jr. via KO (elbows) at 1:57 of Round 1

- Ian Heinisch def. Cezar Ferreira via unanimous decision (30-27, 29-28, 29-28)

- Marlon Vera def. Guido Cannetti via submission (rear-naked choke) at 1:31 of Round 2

- Cynthia Calvillo def. Poliana Botelho via submission (rear-naked choke) at 4:48 of Round 1

- Michel Prazeres def. Bartosz Fabinski via submission (guillotine choke) at 1:02 of Round 1

- Alexandre Pantoja def. Ulka Sasaki via submission (rear-naked choke) at 2:18 of Round 1

- Austin Arnett def. Humberto Bandenay via unanimous decision (29-28, 29-27, 29-27)

- Laureano Staropoli def. Hector Aldana via unanimous decision (30-27, 30-27, 30-27)

- Jesus Pinedo def. Devin Powell via unanimous decision (30-27, 30-27, 29-28)

- Nad Narimani def. Anderson dos Santos via unanimous decision (30-27, 30-27, 30-27)