Off spinner Ashwin, who had grabbed his second five-wicket haul in the third Test when he picked up 5 for 156 in the huge visiting team first innings total of 590, was last out for 103 off 118 balls. He has scored two centuries in first-class cricket before today`s feat.
The 25-year-old`s fine all-round feat of grabbing five wickets and scoring a hundred in the same Test match helped him join a short list of only two Indian players to have done so ? Vinoo Mankad in 1952 (184 and 5 for 196 at Lord`s against England) and Polly Umrigar (172 not out and 5 for 107 against West Indies) at Port of Spain in 1962.
The Tamil Nadu cricketer`s knock included 15 fours and two sixes during the extended second session as the hosts were dismissed for 482 in 135.4 overs that gave the visitors a lead of 108 runs after India added 106 runs during the session while losing their last four wickets.
Ashwin was in danger of losing out on his century in only his third Test when last batsman Pragyan Ojha joined him when he was 16 short of the mark.
Ojha remained unconquered on 0 after facing 14 balls and as Ashwin got the remaining runs with aplomb to reach his ton before holing out to short mid wicket fielder Adrian Barath off Ravi Rampaul off the very next ball.
The batsmen out in the second session before Ashwin were Virat Kohli, who notched his maiden half century by making 52 in 111 balls with five hits to the fence, Ishant Sharma (5) and Varun Aaron (4).
Kohli added 97 crucial runs with Ashwin for the seventh wicket in 148 balls and 93 minutes to help the home team avoid the follow on after the fall of V V S Laxman (32), Tendulkar (94) and skipper Mahendra Singh Dhoni (8).
The Delhi right hander was dismissed by leg spinner Devendra Bishoo whom he drove to Fidel Edwards at mid on, six balls after reaching his maiden 50 with a steer for one run in 85 minutes.
When Kohli got dismissed by Bishoo, who should have got the batsman`s wicket on 43 but for wicket keeper Carlton Baugh grassing an easy catch, India were trailing the visitors by 162 runs and a flurry of wickets could have provided the visitors a bigger lead.
But Ashwin showed good sense and batted with purpose, playing accomplished shots. He was well supported by Sharma who made only five runs but kept the rival bowlers at bay for 44 minutes during which the score advanced by 27 runs.
Ashwin struck leg-spinner Bishoo for two sixes too over long on, besides playing some delicate glances and drives to the off. His stand with Kohli took India to a safer position from where they were when they joined hands.
With the wicket playing true, a draw appeared to be the most obvious result in the final match of the series in which India have grabbed an unassailable 2-0 lead by winning the opening two Tests at Delhi and Kolkata.
In the morning, all eyes were on Tendulkar who was 33 short of his long-awaited landmark after having come close on a few occasions since March 12, when he hit his last international hundred.
But Tendulkar missed his elusive mark after stroking his way magnificently to 94 but thereafter India placed themselves in a good position to avoid the follow on that they died in the post-lunch period.
Tendulkar was racing imperiously to his landmark three-figure mark after resuming at his overnight 67 in a team score of 281 for 3 when his dream was shattered, albeit temporarily, by visiting team`s fast bowler Rampaul bowling with the second new ball taken immediately on resumption of play at the Wankhede Stadium.