Day two saw host batsmen dominating throughout as out-of-form skipper Cheteshwar Pujara's also hit a brilliant ton to remain unbeaten on 139 when the stumps were drawn. Giving him company at the other end was Abhishek Nayar on 10.
India A were leading by 66 runs in their first innings with as many as seven wickets remaining at the KSCA Stadium.
Seeking to make a comeback to the national team, Gambhir, who was woefully out of form for a long time, notched up 123 off 236 balls with the help of 11 boundaries.
Delhi left-hander, who seemed determined to play a long innings in his quest to force the national selectors to sit up and take note, stroked his way to his 35th first-class century by flicking spinner Ashley Nurse for a boundary. But before that he survived a loud leg before appeal off Nurse.
The opener showed glimpses of his old self, mixing aggression with defence as per the situation. Gambhir was flamboyant in the morning session when he cracked eight scintillating fours, but looked guarded in the second session as he did not score a single boundary.
Most of his runs after lunch came in singles and twos, reflecting his determination not to fish at any away-going ball, which the WI A bowlers had offered to him in plenty.
Gambhir got good support from Pujara, who scored his runs after batting watchfully for nearly five hours and hitting 15 exquisite boundaries.
