With less than a week to go before the World T20, Zimbabwe announced they were making three changes to their squad, all because of injuries suffered in practice matches. Neville Madziva and Luke Jongwe were big misses, but Zimbabwe had enough depth in the seam department to cope. Graeme Cremer, on the other hand, seemed irreplaceable.

In six T20Is this year, Cremer had taken 10 wickets at 15.80, and conceded less than seven runs an over. In ODIs this year, he had averaged 25.00 while giving away only 3.57 runs an over. Losing a legspinner in that kind of form, and with the experience of 96 international games, is a punch in the gut for any team that is about to play a world event in the subcontinent.

Into the breach stepped Wellington Masakadza, a 22-year-old left-arm spinner with 10 ODIs and three T20Is under his belt before the tournament. He largely slipped under the radar in the opening game against Hong Kong. On Thursday against Scotland, he was forced onto the hot seat: defending 147, Zimbabwe gave him the new ball.

Facing up at the other end was George Munsey, fresh from blasting a 29-ball 41 against Afghanistan. Munsey's last two boundaries in that innings had come off reverse-sweeps. He brought out the shot against the second ball Masakadza bowled, hitting it firmly but straight to short third man.

You are only allowed two fielders outside the 30-yard circle in the Powerplay overs of a T20 game. For a left-arm orthodox spinner bowling to a left-hand batsman, those two fielders have to be on the leg-side boundary, almost out of necessity. Consequently, backward point and third man have no choice but to remain inside the circle. If you can play it well, the reverse-sweep is a deadly weapon in that situation.

Munsey went for the reverse-sweep again, next ball, and missed. No problem. He reverse-swept the next two balls for four, over the fielder at short third man.

One ball remained in Masakadza's over. Third man went back on the rope, and a fielder came in off the leg-side boundary. Munsey jumped out of his crease, probably looking for the big hit with the turn. Masakadza bowled it shorter and wider than he wanted. Munsey, unbalanced, jabbed at the ball and missed. The keeper did the rest.

"He [jumped out a little early], and I was under pressure a little," Masakadza later said. "I just pulled my length in and fired it wide."

Another wicket fell in the next over, but Scotland continued to target Masakadza. He was still a left-arm spinner bowling in the Powerplay, and at the other end now was another left-hander, Matt Machan. The two men back on the leg side were long-on and deep midwicket. This meant square leg and fine leg were inside the circle.

Second ball of the over, Machan swept Masakadza and bisected these two. Masakadza moved square leg back, and moved long-on to mid-on. Knowing the next ball would be straighter, Machan moved away from his leg stump, making room to clout the ball over mid-on's head. Four more.

For the second time in two overs, Masakadza had been hit for two fours in two balls. This time he did not make another field change. He dared Machan to go over mid-on again. Machan stepped out. Masakadza probably saw this coming, and bowled it flatter and quicker. Machan went through with his shot, failed to get the elevation he wanted, and mid-on took a dolly.

"Obviously, when you're bowling, you still have to bowl your six balls even if you get hit the first two balls for boundaries," Masakadza said. "And you will have to at least try and get the batsman not to hit more, so there was a bit of variation [in pace]."

Scotland were 20 for 3. They slumped further, to 20 for 4 and 42 for 5, before Richie Berrington and Preston Mommsen came together to start worrying Zimbabwe all over again. When Masakadza began his final over, Scotland needed 57 from 36 balls. This would be the last over bowled by a spinner, and Scotland would target Masakadza once again.

There were more fielders on the boundary now, and the right-handed Mommsen was on strike. Looking at Masakadza's stock left-arm spinner's field, Mommsen eyed the big gap between long-off and the sweeper cover. To hit that gap, he would have to go inside-out, over extra cover - a common ploy in limited-overs cricket.

First ball, Masakadza saw Mommsen making himself room and bowled it wider. He reached out and sliced the ball over backward point, not really timing it, and picked up two. Next ball, Mommsen stepped away again. Masakadza followed him this time, denying him swinging room. Instead of chipping the ball over the fielder at short extra, Mommsen hit it straight to the man.

That was the big wicket, and four balls later Masakadza killed off Scotland's challenge, dangling one up slower and turning it past the advancing Safyaan Sharif. He had begun the game as the inexperienced weak link Scotland would target, and ended it as the match-winner.

Karthik Krishnaswamy is a senior sub-editor at ESPNcricinfo