Kevin De Bruyne compared Rasmus Hojlund to his former Manchester City team-mate Erling Haaland as the Dane was one of several ex-Man United players to star in the Champions League.
The Red Devils missed out on the competition after losing last season's Europa League final to Tottenham, but several of their former players were in action on Wednesday.
Hojlund, who was dropped from Ruben Amorim's squad at the start of the season, continued his impressive start to life with Napoli.
The forward was named as the player of the match after netting twice for the reigning Italian champions in their 2-1 win over Sporting Lisbon.
Hojlund opened the scoring in the 36th minute by racing onto a through ball from De Bruyne before calmly finishing.
After Sporting Lisbon equalised in the second half from the penalty spot, the De Bruyne and Hojlund combination restored Napoli's lead, with the Belgian crossing for the forward to head in the winner.
Rasmus Hojlund was named player of the match as Napoli earned a 2-1 win over Sporting
The former Man United forward scored twice for the Italian champions to earn the victory
Kevin De Bruyne compared Hojlund to his former Manchester City team-mate Erling Haaland
'It was the night you dream of, playing in the Champions League,' Hojlund told UEFA post-match.
'I celebrated touching the Napoli badge because I'm happy to play here and the Champions League badge because I love to score in Europe.'
De Bruyne lauded Hojlund post-match by offering a comparison to his free scoring former team-mate Haaland, while highlighting how the Dane can improve further.
'We deserved the win today. I was trying to get into that space for the first goal and was waiting for the right moment to pass it to Rasmus, luckily he did the rest. I think Rasmus is growing a lot and is very similar to Haaland.
'I think they are very similar because they both like to attack the depth. Maybe Hojlund comes to play the ball towards us more, but I think he needs to attack the space a lot because he can score and give us a big hand.'
De Bruyne's comments echo a comparison made by Hojlund ex-Atalanta manager Gian Piero Gasperini, which he made prior to the forward's £72m move to Man United in 2023.
Hojlund had already scored three times in his first five matches for Napoli since making a move on an initial loan, which carries an obligation to buy for £38m.
The forward was far from the only Man United reject to star in the Champions League on Wednesday.
Marcus Rashford provided the assist for Ferran Torres goal for Barcelona against PSG
Anthony Elanga was named player of the match after Newcastle's 4-0 win over Union Saint-Gilloise
Ex-Man United loanee Marcel Sabitzer scooped the award after Dortmund beat Athletic Club
Anthony Elanga and former loanee Marcel Sabitzer also scooped player of the match awards, while Marcus Rashford assisted Barcelona's goal against PSG.
Elanga has continued his rise since leaving Man United for Nottingham Forest for £15m in 2023, with the winger's performances then earning him a £55m move to Newcastle.
He played a key role in Newcastle's first two goals in their 4-0 win over Union Saint-Gilloise on Wednesday.
His cross to Sandro Tonali led to Newcastle's first goal with the Italian's shot flicked in by Nick Woltemade, before he earned a penalty after being brought down by Fedde Leysen for their second goal.
Sabitzer, who had a short loan spell at Man United in 2023, was named player of the match as Borussia Dortmund earned a 4-1 win over Athletic Club.
The Austrian was credited with an assist for the Bundesliga side's fourth goal in their impressive win.
While both Elanga and Sabitzer departed Man United prior to Sir Jim Ratcliffe and Ineos' arrival at the club, the performances were a reminder of the talents that have underwhelmed at Old Trafford in recent years before impressing elsewhere.