(CNN) -- Virender Sehwag plundered the second-fastest Test double hundred as India piled on an incredible 443-1 off just 79 overs on the second day of the deciding third match against Sri Lanka in Mumbai.
The opener reached 284 off only 239 balls at stumps on Thursday -- the third-highest individual score in one day's play -- for his sixth double ton, a record for India, and is poised to become the first player to complete three triple-centuries.
India, seeking a victory which would take the No. 1 Test ranking above South Africa and seal a 2-0 series victory over second-placed Sri Lanka, have already achieved a first-innings lead of 50 runs.
The tourists had resumed on 366-8 with Angelo Mathews unbeaten on 86, but the all-rounder fell one run short of his maiden Test century when he was run out by the narrowest of margins following a throw by Sachin Tendulkar.
When wicketkeeper Mahendra Singh Dhoni lodged the bails, replays showed that Mathews' bat was over the line -- but not grounded -- thus he departed as ninth man out for 99 off 131 balls.
Young left-arm spinner Pragyan Ojha then claimed his third wicket to go with the four that his senior partner Harbhajan Singh claimed on Monday as Sri Lanka were all out for 393, 27 minutes into the day's play.
That brought Sehwag and inexperienced opener Murali Vijay to the crease, and they launched a blistering attack on the Sri Lankan bowlers putting on 221 in just 39 overs.
Vijay, playing only his second Test, was finally trapped leg before wicket by spinner Rangana Herath, having made 87 off 121 deliveries, with 10 fours and a six.
The explosive Sehwag, who made 131 in India's innings victory in Kanpur, then found another solid partner in Rahul Dravid, who calmly fed him the strike in his patient 62 off 121 balls.
Sehwag passed three figures from 101 deliveries and then raced to his second century off just 67 -- the only man to pass that milestone quicker is New Zealand's Nathan Astle, who took 153 balls against England in 2002.
"I missed out on a double-century in the last Test in Kanpur and I wanted to make amends," Sehwag told reporters. "I batted the best way I thought was possible.
"I was cautious at the start because I did not want to give the opposition any chances as I had done in the two previous matches. I thought I would bide my time, see off the new ball and then take my chances."
Sehwag hit 40 boundaries and seven sixes, and was particularly hard on Sri Lanka's veteran world record-holder Muttiah Muralitharan, who has struggled all series.
The 37-year-old, who has taken 788 Test wickets, conceded 119 runs off his 20 overs.
"Muralitharan is a big challenge and when playing a quality bowler like him you have to attack early, otherwise he will dominate," Sehwag said.
"I thought rather than let him dominate, I would attack him from the start and keep him on the back foot."
Daryl Tuffey celebrated his comeback after a five-year absence with two wickets as he replaced injured strike bowler Shane Bond, while captain Daniel Vettori took 3-42 with his left-arm spin as bad light ended play early.
Imran Farhat and Salman Butt put on 60 for the first wicket but then fell in quick succession along with captain Mohammad Yousuf as Vettori snared two wickets in three balls.
Australia fast bowler Brett Lee has had elbow surgery in a bid to save his career.
The 33-year-old needed an operation to correct a damaged ligament after twice breaking down this year amid fears he would have to retire, and is not expected to be fit again before March.
The player, who missed the Ashes defeat to England, has taken 310 Test wickets in 76 matches and 324 one-day scalps in 186 appearances.