Ever since India's tour of Sri Lanka last year, R Ashwin has regularly bowled without a fielder at cover against right-hand batsmen in Tests. He has tried to tempt them to hit against the break, into that gap, and bowl them through the gate. Wary of his dip and command of length, the batsmen have ignored the bait and played him with caution.

Not so Rajendra Chandrika, against Ashwin's first ball in Antigua. Chandrika went for the drive, connected sweetly, and picked up four runs. He tried the same shot three balls later; this time the ball dipped on him and turned past his inside edge. Instead of crashing into the stumps, the ball bounced over them.

Later in West Indies' first innings, Ashwin bowled a similar delivery to Shane Dowrich, with near-identical consequences. Near-identical, because this ball spun past leg stump rather than bouncing over the stumps. It beat the keeper and went for four byes.

For his first 24 overs of the match, Ashwin was wicketless. The closest he came was when Dowrich edged him, and Ajinkya Rahane claimed a low catch diving forward at slip. The decision went to the third umpire, who ruled it not out when replays seemed to show the ball dying a couple of centimeters short of Rahane's fingers.

For some reason, perhaps because he was bowling unusually short spells - in the first innings, they lasted three, five, three and six overs - he took time to achieve rhythm, and dropped short far more frequently than he has done in recent months. Kraigg Brathwaite, Darren Bravo and Dowrich cut him for fours in the first innings, and his second innings seemed to be going the same way when Marlon Samuels punished a short, wide ball in his fifth over.

Samuels hit him for two more fours in the same over, through the covers and over mid-off. Ashwin had scored a century in India's innings; it looked like he wouldn't have too much to celebrate with the ball.

His struggle, though, had little to do with how the West Indies batsmen were playing him. There always seemed a hint of insecurity in their defence, a sense that they weren't quite at ease with his drift and dip. It felt like one good spell could change Ashwin's fortunes. But no one could have predicted how drastically they would change.

When the players returned after an early lunch forced by a brief shower, Ashwin began to worry Samuels. Three times in the same over, the ball dipped and landed shorter than Samuels expected, and his forward press left him a long way from the pitch of the ball. Twice the ball beat his inside edge and hit front pad. Once it brushed his outside edge and rolled away wide of slip.

A greater reliance on the offbreak has often been heralded as the reason for Ashwin's renaissance over the last year and a half. That is only half the story, and doesn't acknowledge that his offbreak is also far more potent than it used to be

Apart from the two runs that accrued from that edge, Ashwin didn't concede a run in his first two overs after lunch. In his third, he seemed to drop another ball just a tad short. Chandrika rose to cut, but the ball jumped at him, and a thick edge flew wide of slip.

Two balls later, Ashwin broke through. The front-foot flick is a hazardous shot against an offspinner when he's getting the ball to dip, particularly when he has a packed leg-side field, as Ashwin did right through the match, and when those leg-side fielders include a short leg for the inside-edge onto pad and a short midwicket for the uppish, early flick.

Chandrika's flick didn't end up in the hands of short leg or short midwicket. It merely grazed - or perhaps didn't, so inconclusive were replays - his inside edge, and ballooned to the wicketkeeper off his pad. At any rate, Chandrika didn't protest.

In Ashwin's next over, another batsman paid the price for that loose front-foot flick. Jermaine Blackwood's Test match ended with no runs from ten balls faced.

His stay could have been even shorter. The first ball of the same over, he had groped forward to defend a flighted ball outside off stump, and had found himself playing down the wrong line. The ball had curled away from him in the air, and turned back just a touch and narrowly missed his outside edge.

A greater reliance on the offbreak has often been heralded as the reason for Ashwin's renaissance as a bowler over the last year and a half. That is only half the story, and doesn't acknowledge that his offbreak is also far more potent than it used to be. After Ashwin ironed out a few technical kinks in his action, the ball now comes out of his hand exactly as he wants it to, more often than not, and does more in the air and off the pitch than it used to.

Thanks to the amount of dip he gets, he has that much more chance of beating the inside edge when he turns it big. And thanks to the away-drift he can achieve - aided on the fourth day in Antigua by a strong breeze blowing across the ground, from east to west - he can also beat the outside edge with his offbreak.

Two overs after he had beaten Blackwood's bat with drift, he bowled a similar delivery to Samuels. This time the line was just a little straighter, and when the ball curled away just enough to make Samuels play down the wrong line, and turned minimally enough to beat his outside edge, the only thing that remained in its path was the top of off stump.

Just like that, Ashwin had three wickets. It only took him six more overs to complete his 17th Test-match five-for. It seemed all too easy, and, truth be told, it was.

West Indies' batsmen kept making the same mistakes. Just like Chandrika and Blackwood before him, Roston Chase pushed at the ball, playing far out in front of his body. And then, ignoring the dip Ashwin was getting nearly every ball, Jason Holder drove against the turn, and left a big gap between bat and pad.

Just like they had done against Mohammed Shami in the first innings, West Indies had collapsed at the first sign of sustained pressure.

Karthik Krishnaswamy is a senior sub-editor at ESPNcricinfo