The centre-back is determined to give every ounce of effort as the club close in on their first Ligue 1 title since 1994
If Olympique de Marseille fail to beat Bastia on Saturday, then the capital club will become champions providing they get a victory on Sunday.
And Alex insists the squad are putting in the necessary work as they bid to lift the club's first Ligue 1 title since 1994.
"Of course this is the most important game of the season,” he told GMP.
“All the players are preparing for this meeting. We've got all week to work. We worked hard today and will continue until Sunday to win. Everyone will look at the results of Marseille on Saturday, obviously. But for us, no matter, we must do the work to win on Sunday and be a champion."
The Brazil international has won league titles with every single club he has played for in his career to date, having enjoyed domestic success with Santos, PSV and Chelsea.