The seven-time Formula 1 World Champion was tussling it out with Verstappen after the Red Bull man had dropped back down the field following a painfully slow pit-stop.
The world-famous Monza track - known for its speed - can get very narrow in places and it proved to be just far too narrow for Verstappen and Hamilton.
With neither of these remarkable motoring gladiators unwilling to relent and give an inch, contact was almost inevitable.
And, only seconds after Hamilton emerged from the pits following a messy pitstop of his own, the pair came together in a crash that saw them both forced to retire from the race.
Thankfully, this particular incident was at slightly slower speed than the now infamous collision at Silverstone earlier in the year, but it was no less terrifying.
As their rear-wheels collided, Verstappen's gripped and flicked his car up in the air and over Hamilton.
As the cars then careered towards the gravel, the Red Bull wheel came down on top of the Mercedes, missing Hamilton by only inches.
Now, incredible slow motion footage has emerged showing that the reigning champion was frightfully close to serious harm.
In fact, had it not been for the halo safety device - designed to protect drivers who sit exposed in the cockpit - Lewis would have been in serious trouble.
Thank goodness for the introduction of the halo.
Romain Grosjean was similarly thankful for the device last year after he smashed into the barriers in Qatar before his car ignited in a ball of flame.
Meanwhile, back in Italy, it was the McLaren lads wearing the widest of smiles as Daniel Ricciardo recorded his first win for the orange machine.
He was followed closely behind by partner in crime Lando Norris as the British side recorded a massive one-two finish.
It was an afternoon to forget for Red Bull however, after Sergio Perez was slapped with a five second penalty forcing him into a fifth place finish.News Now - Sport News