Casemiro opened the scoring in some style on Wednesday night in the 5-2 drubbing of Leicester - with his 25-yard stunner eliciting a joyous reaction from Ruud van Nistelrooy over on the touchline.
In their first game since Erik ten Hag's departure earlier in the week, Manchester United turned on the style in the fourth round clash, putting five past Steve Cooper's Foxes.
Casemiro and Bruno Fernandes scored twice, with Alejandro Garnacho grabbing the other, while Bilal El-Khannouss and Conor Coady netted in the first half for the visitors.
But in his first game as Man United's interim manager, Van Nistelrooy was left stunned by his defensive-midfielder's absolute screamer of an opener.
Casemiro's reputation in the game has plummeted since he joined United from Real Madrid two summers ago, but he reminded everyone just what a world class performer he is against Leicester.
Garnacho carried the ball down the left before checking inside and playing a pass in the direction of Fernandes a quarter of an hour into the clash, only for the Portugal star to step over the ball and let it run.
Into Casemiro's path it went and the midfielder didn't pass up on the opportunity. He took a touch out of his feet and let loose a curling effort straight into the top right corner of the goal in sublime fashion.
Naturally, Casemiro was quick to run over to the fans and revel in his world class effort, and he was soon joined by his team-mates.
But over on the touchline Van Nistelrooy, perhaps known better for his finishing inside the box, but not many know more about scoring goals than him, was clearly taken aback.
He was left with a huge smile on his face and pumped his fists in the air several times in celebration.
The former United and Real Madrid striker can hardly have hoped for a better evening, his side finding the back of the net five times in his first game as interim boss.
United's reward for a fine performance at Old Trafford is a trip to north London where they will face Tottenham for a chance to make the last four of the competition, and perhaps go even further and win a second Carabao Cup in three years
Impressive those his side were, it is unlikely to lead to an extended spell in the dugout, however, with the club in talks with Sporting over highly-regarded manager Ruben Amorim.
Discussions are still thought to be centred on the Portuguese boss' notice period, which is believed to be weeks rather than days, leading to reports that he would not be able to take over until after the international break.
Should United bring in Amorim, as well as his coaching staff, it would set them back almost £13m, according to reports.