World number three Gauff will play Magda Linette in the third round in Rome after prevailing despite being far from her best in a match which signalled more progress from her up-and-coming opponent.
Canadian Mboko played with a maturity which defied the 153 places separating her from Gauff in the world rankings in a prime-time clash on centre court.
The 18-year-old has risen from 333 to 156 since the start of the year and the Foro Italico crowd quickly took to her confident and powerful play.
Mboko had Gauff on the ropes in the first set, breaking the former US Open winner four times, but eventually gave way to her more experienced opponent who is one of the favourites for overall victory after losing to Sabalenka in the recent Madrid final.
“It was a tough match, Victoria came out playing some tough tennis, I knew she was going to do from watching some of her previous matches,” said Gauff.
World number one Sabalenka swept past Russia’s Anastasia Potapova 6-2, 6-2 in just over an hour.
Sabalenka will play Sofia Kenin in the next round after the American beat another Russian in Anastasia Pavlyuchenkova in straight sets, 6-3, 6-0.
The 27-year-old Sabalenka has reached the final of her last four tournaments, winning both in Madrid and in another 1000 series in Miami.
Alcaraz got past Dusan Lajovic 6-3, 6-3 in one hour and 23 minutes in his first match since suffering a thigh injury in his Barcelona Open final defeat to Holger Rune last month.
The Spaniard showed some signs of ring rustiness with 22 unforced errors but saw off Serbian qualifier Lajovic and was positive about his comeback display.
“It was a great performance, a great level, which was surprising for me a little bit but I’m just really happy,” said Alcaraz.
Alcaraz will now face Laslo Djere, a 6-0, 6-3 winner over Alex Michelsen, in the third round as he eyes a potential final with world number one Jannik Sinner in the Italian capital.
Sinner will make his comeback from a three-month doping ban on Saturday when he takes on Mariano Navone in front of what will be a partisan crowd.
Alcaraz said he would take it easy on his day off, keep an eye on Sinner’s match and go to watch his friend Patric play for Serie A football club Lazio against Juventus at the nearby Stadio Olimpico.
Reigning Rome champion Alexander Zverev also strolled into the next round, beating Argentina’s Camilo Ugo Carabelli 6-2, 6-1 in the last match of the day on centre court.
Home hope Lorenzo Musetti opened his week, his first in the top 10 of the men’s world rankings, with a 6-3, 6-2 win over qualifier Otto Virtanen.
Musetti, losing finalist in Monte Carlo last month, has American Brandon Nakashima next and could face Daniil Medvedev in the last 16 after the 2023 Rome champion easily saw off Britain’s Cameron Norrie 6-4, 6-2 to set up a third-round clash with Alexei Popyrin.
Ninth-seed Rune will play Corentin Moutet, who went through after fellow Frenchman Ugo Humbert withdrew injured, in the third round after winning a thrilling match with Francisco Comesana 3-6, 6-3, 6-4. (AFP)
