The 21-year-old Argentinian midfielder was recalled from a loan spell with Boca Juniors in January and has just helped his country’s under-23s qualify for this summer’s Olympic Games tournament in Japan.
He arrived in Sussex on Friday before heading to the American Express Elite Football Performance Centre for a look around on Saturday, accompanied by his father Carlos, who played three times for Argentina.
And Mac Allister, who made his Argentina debut earlier this season, believes he is a better player for his experiences with Boca, having initially joined Albion in the 2019 January transfer window.
“I’m really happy and I’m full of excitement to get going,” he said. “In the middle of the Olympic tournament it broke that I could come here and I was happy with that.
“Was I expecting to come here earlier? The truth is I always think about the present and at that time I was focusing on the Olympics tournament.
"I let other people worry about the situation but I am pleased to be here now and looking forward to my first training session and to meeting the other players.”
Mac Allister made 12 appearances in Argentina’s domestic competition for Boca Juniors as well as playing in the Copa Libertadores and says he experience of playing for one of South America’s top clubs made a big impression, especially as he was used in different midfield roles.
“I have changed a lot in the year since I signed for Brighton,” he said. “My time at Boca helped me mature and learn a lot of things. I think it will serve me well for my future.
“I have matured in a lot of ways but as a person I try to always be the same. I have those values that my parents have instilled in me.
“As a player, I have learnt about playing in different positions. At Boca I played a lot in a midfield role out to the left and that is a position where I can do well but everybody knows that I feel most comfortable playing in behind a No.9.
“I am a player who can play in various positions and I have done throughout this year. Hopefully that will be useful for the team.”