Olympic champion Zheng Qinwen and sixth seed Casper Ruud rallied to make the Australian Open second round on Sunday
Fritz is set to face either Jannik Sinner or Casper Ruud in the final on Sunday.
World No. 3 Alcaraz beat Rublev 6-3, 7-6 (10/8) to lift himself off the bottom of the John Newcombe Group.
Alexander Zverev opened his campaign at the ATP Finals in Turin on Monday evening by dispatching Andrey Rublev 6-4, 6-4 in their round-robin opener.
Alcaraz could be eliminated if he loses to second-ranked Alexander Zverev, who faces Andrey Rublev in his opener later on Monday.
Rafael Nadal and Casper Ruud saved a match point in the deciding set tie-break to reach the semi-finals of the doubles in Bastad on Wednesday, hours after the Norwegian was knocked out of the singles.
It was Nadal's first match since the 38-year-old fell to Alexander Zverev in the opening round at Roland Garros on May 27.
Carlos Alcaraz defeated Australia's world number 69 Aleksandar Vukic 7-6 (7/5), 6-2, 6-2 on the back of 42 winners.
Alexander Zverev holds a career 5-4 winning record against Carlos Alcaraz, including a victory in their only previous Roland Garros meeting in the 2022 quarter-finals.
Alexander Zverev advanced to his fourth successive French Open semi-final with a 6-4, 7-6 (7/5), 6-4 win over Australian 11th seed Alex de Minaur on Wednesday.