The defender started for AC Milan in their crucial Champions League clash away at the Magpies and bailed his teammates out on 20 minutes.
Both sides need a win for a chance to progress to the last 16, and it was Newcastle who started brighter and would've gone ahead were it not for Tomori's intervention.
Joelinton was played into the area and cut back towards Miguel Almiron, who looked destined to score from close-range.
However, Tomori denied him with an excellent stop on the line, doing so with the outside of his right foot.
It could prove to be a crucial clearance, and fans on social media were left in awe of the Englishman's efforts at the back for Milan.
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Taking to X, one said: "That's one of the best tackles I've ever seen. Tomori with an absurdly great moment."
"That's an incredible piece of defending from Tomori!" added a second.
A third said: "That's insane by Tomori. One of the finest tackles you'll see."
"Fikayo Tomori with the block + clearance of the year! Damn," added a fourth with a fire emoji.
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Joelinton then put Eddie Howe's men ahead on 33 minutes with an emphatic finish to set St. James' Park rocking.
However, Christian Pulisic equalised for Milan just before the hour mark, doing so after a smart flick from Olivier Giroud.
Samuel Chukwueze then gave the visitors a late lead with a curling finish on the counter-attack to send them to the Europa League and Newcastle out of Europe.
This season's 'Group of Death' certainly lived up to the hype, and Tomori's tackle encapsulated the drama Group F had on display.