The Argentine superstar was very keen to work under Mourinho, shortly after he joined the Blues from FC Porto.
The Portuguese manager had won the Champions League with Porto the previous season.
Messi was just 16 when Mourinho arrived at Stamford Bridge at the time, turning 17 later that month.
It is believed that this was the first time he tried to leave Barcelona.
Over this summer, Messi also expressed his desire to leave the Nou Camp.
The 33-year-old whose contract expires in June 2021, eventually made a u-turn and remained with the LaLiga giants.