India need to a victory at the Eden Gardens to save the series and hang on to their top spot in the rankings. After South Africa make 296, Sehwag blitzes a 174-ball 165 to lay the platform for a big first-innings score. India goes on to win by an innings, and Sehwag becomes the No. 1 Test batsman in the world.
He unleashes what he terms his is best innings in one-dayers: careering to a 102-ball 146 against Sri Lanka in Rajkot that propels India to a seemingly safe 414. India just went about winning it, though - by three runs.
Even by his own standards, the 293 against Sri Lanka at the Brabourne is astounding. The brutal assault breaks a string of records - the most double-centuries by an Indian, the second-highest number of 250-plus scores, the most runs by an Indian in a day - and gives India the launchpad to a win that would take them to the No. 1 spot
A shoulder problem sustained during the IPL forces him out of the ICC World Twenty20, and subsequently a tri-series in Sri Lanka and the ICC Champions Trophy.
He blitzes a century off 60 deliveries as India sweep to a massive series-winning victory in Hamilton. When rain interrupts his onslaught, India is 201 off 23.3 overs: the Duckworth/Lewis target at that stage is only 118.
The first Test since the Mumbai terrorist attacks in November is more remembered for Sachin Tendulkar's emotional century that sealed the win over England, but is Sehwag's full-throttle 83 on the fourth evening that sets India on course to overhauling the stiff target of 387 in Chennai.
A spectacular year continues when he makes a sublime double-century against the wizardry of new spin sensation Ajantha Mendis and the old master Muttiah Muralitharan in Galle. He contributes 201 out of 329 and carries his bat, even declining singles when batting on 199 with the last man.
In his next Test innings he blazes to the quickest triple-hundred, taking 278 deliveries to reach the mark, joining Don Bradman and Brian Lara on the list of players making two scores in excess of 300. On a flat track in Chennai, he flogs 257 runs on the third day alone. South Africa coach Mickey Arthur calls it the 'best Test innings I have ever seen'
In his stunning resume, there had been no second-innings centuries but in Adelaide - his second Test after making a comeback - Sehwag crafts 151, unusually dropping anchor after reaching his century, to save India when the established batting stars flop. The next highest score is MS Dhoni's 20.
Though he had been in and out of the limited-overs side over the past year, there's no hint of a Test recall, and he is left out of the preliminary squad for the Australia tour. Surprisingly, he is among the 16 members that the selectors finally pick for the series, and he returns to energies India's top-order during the famous Perth win.
After a string of listless performances, particularly in the DLF Cup in Kuala Lumpur, he is stripped of the Test vice-captaincy. A disastrous tour of South Africa ends with him playing in the middle-order for the deciding Test in Cape Town, after which he is left out of Tests for a year.
He and Rahul Dravid nearly break the record for the largest opening partnership in Tests, when they put on 410 on a featherbed in Lahore. They fall three short of the 50-year-old mark when a nick to the keeper ends the stay of Sehwag, who later says he was unaware of the previous record.
He turns in a dazzling Man-of-the-Series performance at home against Pakistan, rattling off scores of 173, 81 and 201 in the three Tests at his usual frenetic pace, but it still isn't enough to give India a series victory.
He has his troubles in the one-day format but Test cricket continues to be easy for Sehwag, as he batters the South African bowlers in the two-match home series. First, there's an insolent 164 in Kanpur followed by a typically belligerent 88 at the Eden Gardens.
In nine hours of sustained hitting, he becomes India's first triple-centurion, in a high-pressure match against Pakistan in Multan. His 309 is the bedrock of India's massive total, and sets up the side for their first Test win in Pakistan.
He constructs one of the great innings on the opening day of a Test, lashing 195 runs against Australia at the MCG in a little over five hours. Studded with 25 fours, he falls short of his first Test double-century when attempting to clear long-on just one ball after he had smashed his fifth six.
With a place in the semi-finals at stake in the ICC Champions Trophy, he smashes a 104-ball 126 against England at the R Premadasa Stadium to take India to the target of 270 within 40 overs. Before this, no team had successfully chased more than 244 at the venue.
With the Test middle-order packed, he is promoted to the top of the order on the tour of England. He continues to match every challenge set for him - in his first two Tests as opener, he blasts a carefree 84 and a boundary-filled 106.
In his next Test in Port Elizabeth, he is among the six Indian players penalised by the match referee Mike Denness. Sehwag is given a one-Test ban for dissent and for trying to intimidate the umpire by charging at him. A huge controversy erupts, the Indian board called the rulings 'biased' and 'inconsistent', the third Test in Centurion is declared unofficial and only after endless negotiations with the ICC do India accept Sehwag's ban.
Initially considered a limited-overs specialist player, he shows he can cut it in Tests with a sparkling century on debut - in South Africa after walking in with the team floundering at 68 for 4. His reviving 220-run stand with Tendulkar comes off just 47.2 overs.
Asked to open the innings in the absence of Sachin Tendulkar, to whom he is compared early in his career, he hammers a 69-ball century against New Zealand at the Sinhalese Sports Club to easily steer India to the target of 265 and a place in the final of the Coca-Cola Cup.
His first game-changing performance at the international level comes in a one-dayer against Australia in Bangalore. A rapid half-century and three important wickets help snap Australia's run of 10 one-day victories
He makes his first appearance at the international level, as an all-rounder batting at No .7, in a one-dayer against Pakistan in Mohali. The 20-year-old hardly looks athletic and flops with bat and ball.