The dream pairing of the only British players to have won Grand Slam singles titles since 1977 came about after Murray pulled out from the men's competition before his match with Tomas Machac a day earlier due to a back issue in the build-up to the grasscourt major.
Murray, who will also be in action in men's doubles with his brother Jamie when they face Australians Rinky Hijikata and John Peers in Thursday's opener, belatedly added mixed doubles to his schedule and Raducanu grabbed the chance to partner him.
"It's a once-in-a-lifetime opportunity," former US Open champion Raducanu told reporters shortly after her 6-1, 6-2 win over Elise Mertens.
"I think Wimbledon is Andy Murray and Andy Murray is Wimbledon.
"Some things are bigger than tennis... to play at Wimbledon with Andy Murray, those things don't come by. At the end of my life... when I'm 70 years old, I know I'm going to have that memory of playing Wimbledon with Andy Murray in a home slam.
"For me, it was an honour to be asked. I just want to see him do well."
Two-time Wimbledon singles champion Murray, who last played in the mixed doubles event in 2019 alongside American great Serena Williams and reached the third round, said he was relishing the chance to play with Raducanu.
"We'd spoken about it a few years ago during the COVID year, but both of us ended up doing quite well in singles so it didn't happen," Murray said.
"And then yesterday I was chatting to my team, they were discussing mixed and last night I messaged her coach and said: 'Look, do you think this is something maybe she'd be up for doing?' He said it was worth asking.
"I asked her and she said she would be up for it. It should be fun. I've played mixed doubles a few times when I was young and then the last time was with Serena. I really enjoyed it, it's something we rarely get to do."
Raducanu may not boast a noteworthy doubles record but said she would give everything for her idol.
"Andy's a hero to us all... I'm super-excited and hopefully I can learn a thing or to about coming to the net or something," Raducanu said.
"I really don't want to let him down. I'm going to be on my best form, trying hard. Probably be more nervous for that than the singles."
Three-time Grand Slam champion Murray, who had hip-resurfacing surgery in 2019, previously said that he was unlikely to continue his career beyond this year and could bow out at the Paris Olympics.
The tennis competition at the Games will start on July 27th.