Both teams came into this game on 10 points in the league phase, while Arsenal were no doubt keen to show that Sunday’s 1-1 draw at Fulham was merely a blip.
And although Gabriel Jesus was only a whisker away from connecting with Mikel Merino’s drilled cross early on, the Gunners initially struggled to break down their opponents through patient possession.
Indeed, a superb long ball from the assured Jakub Kiwior midway through the first half underlined an alternative method of chance creation, but Jesus lacked the composure to beat Radoslaw Majecki from close range.
Jesus soon had another chance to score, this time following an incisive pass by Gabriel Martinelli, but Majecki again denied him.
Given that Arsenal had enjoyed the better of the chances though, it was little surprise when they went ahead on 34 minutes, as Champions League full debutant Myles Lewis-Skelly neatly shifted past Maghnes Akliouche and fed Jesus, who perfectly picked out Saka at the back post for a tap-in.
Odegaard will have then been kicking himself after shooting wide following an opportunistic interception, while Martinelli was treading a fine line just before half-time, having already picked up a yellow card.
Immediately after the break, Monaco signalled their threat from set-pieces as skipper Thilo Kehrer headed off target, but despite showing signs of improvement, the visitors still hadn’t seriously tested David Raya, with Breel Embolo firing wide on the turn.
However, they shot themselves in the foot trying to play out from the back as Mohammed Salisu sold Majecki short, with the keeper forced by the looming figure of Kai Havertz to prod the ball straight to Saka, who tucked home gleefully on 78 minutes to double Arsenal's lead.
And the scoring was complete 10 minutes later, with Havertz diverting in Saka’s shot following the taking of a quick free-kick.
The last time Arsenal failed to score at home was way back in April against Aston Villa, and after taking another step towards the knockout stage here, they will be hoping that their run of finding the net doesn’t come to an end at the Emirates against Everton on Saturday.
Meanwhile, Monaco return to league action the same day, and are still in with a chance of finishing in the top-eight of the Champions League league phase.