The midfielder has surpassed the Real Madrid icon's tally of 79 victories following the 3-1 triumph over AC Milan at Camp Nou
Lionel Messi scored from the penalty spot before Sergio Busquets doubled the hosts' lead, though Massimiliano Allegri's men were offered a lifeline from a Gerard Pique own-goal.
However, the Rossoneri failed the seize their chance at an unlikely point or three and Messi added a second goal to ensure the Blaugrana finished with a two-goal cushion.
Xavi was skippering the side in Carles Puyol's absence, playing in his 141st match (including qualification matches) in the elite European competition.
The victory guarantees a spot in the last 16 for the Catalans as two of Celtic, Milan and Ajax cannot overtake Gerardo Martino's men.
Fellow Liga giant Atletico Madrid also sealed its place in the knockout stages with a victory over Austria Vienna on Wednesday, while Real Madrid is expected to make it out of the group stages in the fifth game week later in November.