Sehwag dominated the first half of the day to hit 180, and Collins controlled the second half to snare four wickets for 75 runs from 20 overs, as India, choosing to bat, reached 361 for four in their first innings when stumps were drawn on the opening day.
Sehwag lashed 19 fours and two sixes from 190 balls and shared two century partnerships that put the Indians in the driveing seat.
He and Wasim Jaffer put on 159 for the first wicket, then he added 139 for the third wicket with India's captain Rahul Dravid, who is also eyeing a hundred of his own.
Dravid, batting with typical resilience, struck 13 boundaries from 158 balls and was unbeaten on 95 at the close.
Collins, playing his first Test in more than a year, after recovering from a back injury, was the pick of the West Indies' bowlers.
Coming into the side to replace his injured brother Fidel Edwards, Collins celebrated his milestone when he bowled Yuvraj Singh for two but he was the only West Indies bowler that looked capable of penetration.
West Indies were made to rue their decision to play four frontline seam bowlers and gained very little from the hard, true, grass-covered pitch.
No West Indies bowler looked to have an answer when Sehwag went on the rampage before lunch.
He narrowly missed out on becoming the fifth player to accomplish the rare feat of a Test hundred before lunch when he tried to slog the final ball of the morning period from Corey Collymore into the leg-side, and only succeeded in slicing the ball to mid-off, where he scrambled a single.
Sehwag got his show rolling with a searing cut off Collins for his first boundary in the first over of the day.
He then got fully warmed up when he struck three fours in Taylor's fourth over.
After India reached 140 without loss at lunch. Sehwag duly arrived at his hundred when he drove Collins to mid-off for a single in the first over after the interval.
He was fortunate though, that on 101 Chris Gayle dropped him at mid-wicket off Taylor in the next over.
Sehwag and fellow opener Wasim Jaffer, a double-century maker in the first Test, looked unstoppable until Collins made the breakthrough.
Bowling with good rhythm, Collins had Jaffer caught at first slip for 43 edging a back-foot drive in the fifth over after lunch.
Collins boosted West Indies' confidence further when Venkatsai Laxman was caught behind for a 10-ball duck chasing a delivery angled across him to set India back on 161 for two.
Sehwag continued to apply himself and batted at a less frantic pace than he did prior to lunch. He soldiered along with the typically sound Dravid to fortify India's position and take the visitors to 230 for two at tea.
Collins continued to chip away and eventually held a return catch to dismiss Sehwag and reached a century of his own when he removed Yuvraj to leave India on 306 for four.
Mohammed Kaif came to the wicket and continued to grind the West Indies attack along with Dravid and they added 55 before the close.
The four-Test series is still level 0-0, after the first Test at the Antigua Recreation Ground ended in a tense draw.
The series concludes with Tests at Basseterre (June 22-26), and Kingston (June 30-July 4).