The duo rescued Mumbai from 44 for 3 in Ahmedabad
The focus was, however, firmly on Rahane who ended the day on an unbeaten 108 from 250 deliveries.
Rahane, who had a mediocre Test series against South Africa recently, got to his century in 212 balls, hitting 14 fours and two sixes along the way. He had managed just 136 runs in six innings in India’s 1-2 defeat in the Test series in South Africa earlier this year.
Another struggling senior India batter, Cheteshwar Pujara, who is playing against Rahane in this match, will also look to get a big knock in the game to ensure the national selectors retain him for the series against Sri Lanka.
With new-ball bowlers Jaydev Unadkat and Chetan Sakariya operating well, Mumbai found themselves in trouble early on, losing openers Aakarshit Gomel (8) and Prithvi Shaw (1) with just 22 runs on the board.
First-change Chirag Jani had No. 3 Sachin Yadav trapped in front as Mumbai slipped to 44 for 3.
However, Saurashtra failed to make any more inroads after that as Rahane and Sarfaraz added 219 runs for the fourth wicket to put their side in a comfortable position at stumps.
Rahane took his time before starting to play freely and got to his 36th first-class hundred.
He got to 99 with a big six against left-arm spinner Dharmendrasinh Jadeja, before getting to the century with a single.
Rahane’s 479 Test runs in 2021 came at an average of 20.82, leading to his sacking from the vice-captain’s post for the tour of South Africa.