The 18-year-old Spaniard beat Brandon Nakashima 4-3 (7-4) 4-1 4-3 (7-4) in an impressive display in Milan, picking up where he left off in his opening encounter with Holger Vitus Nodskov Rune to top Group A.
Rune did claim his first win of the tournament against Juan Manuel Cerundolo, beating him over four sets, but the Dane remains third in the group behind Nakashima.
In Group B, Sebastian Korda also secured his second win from his two matches to move to the brink of securing his own semi-final slot, defeating Sebastian Baez in straight sets 4-3 (7-3) 4-2 4-2.
The American fought back from two sets down in his first match, becoming only the second player in tournament history to do so, but largely avoided any drama this time around.
There was plenty of excitement in the final showdown of the night, however, as Lorenzo Musetti's clash with Hugo Gaston went the distance, with the latter rallying from two sets down only to be beaten 4-2 in the decider.