The 19-year-old Spanish phenom quickly made the break in a one-sided game, from the Portuguese's second service game, which he won "white" on a double fault.
Outflanking the Portuguese's defence with the power and depth of his shots, Alcaraz again took his next serve, escaping 4-1 and then 5-1 on his commitment.
Borges nevertheless managed to get back to 5-3 by exploiting his only break ball of the set, an acceleration of a backhand long line.
Stung to the quick, Alcaraz took Borges' serve again in the next game, pocketing the first set 6-3 in 35 minutes.
The world N.2 accelerated in a second set where he quickly broke away 3-0 before winning this second set 6-1 on a "shutout" game on his commitment, folding the match in 1 hour 03 minutes.
As in the first set, Borges got a break ball in this second act, which he did not know how to exploit this time.
In the eighth, Alcaraz, paradoxically more comfortable against Borges on the opponents' service games than on his own commitments, will find another Spaniard on his way.
Either Bernabe Zapata (41st in the world), semifinalist in Buenos Aires and Rio de Janeiro in February on the South American clay, or Roberto Bautista, still 25th in the world but who seems on the decline at 35 years old.
© 2023 AFP