The Norwegian spent time in Spain during his early years as a professional, joining Real Sociedad on loan from Real Madrid in 2019. He made 36 appearances for the La Liga side, registering seven goals and nine assists before returning to Madrid ahead of his huge move to north London in 2021.
Odegaard's success in the Premier League saw him receive the captain's armband after just one full season with Arsenal - leading the Gunners in close title fights over the last two campaigns.
Merino, who played alongside Odegaard in Spain, believes the 25-year-old has come a long way since his days in the Basque Country.
"It has been a long journey for him and for me," the 28-year-old told reporters. "That finishes now playing together again. We played maybe four, five or six years ago. I saw him as this really talented kid that was just magic in the number 10 position.
"He made my job really easy because he's the one who moves really good in the pockets, he turns, plays quick and for me, as a number eight back in the day, I used to find him a lot and he used to make my passes better. It's amazing how he has evolved and developed.
"Now he's a grown man, the captain, the leader of this club and you can hear the maturity in his voice, how he acts, talks to people and behaves on the pitch. It's great to be back with him again and hopefully we can keep building that relationship and connection that we have."
Merino made his first start for Arsenal during their disappointing 2-0 loss to Bournemouth on Saturday - during which the Gunners were forced to battle on with ten men after William Saliba was shown a red card for fouling Evanilson in the first-half.
