Skipper Heather Knight smashed the first century of the women's Twenty20 World Cup Wednesday as England emphatically got their campaign back on track with a crushing 98-run win over minnows Thailand.

The 2009 champions had looked vulnerable as they crashed to a six-wicket defeat against South Africa in their opening Group 'B' game on Sunday, following a shock 10-wicket hammering by Sri Lanka in their final warm-up last week.

With only the top two from each of the two five-team groups qualifying for the knockout phase, defeat in Canberra would have left their tournament in tatters.

But Knight hit an unbeaten 108 in a tournament-best 169-run partnership with Natalie Sciver (not out 59) to secure the vital win. England's 176 for two was also the highest score by any team so far.

In the later match, Pakistan won their opening clash, beating 2016 champions the West Indies by eight wickets to leave Group 'B' wide open with four teams on two points each. England play Pakistan next on Friday, while South Africa face Thailand.

“We were gutted after the performance the other day so it was very important that we bounced back with a decent performance here, which we did,” said Knight.

“Every game is a must-win game for us now. It was a nice start to get on the board today but we have a long way to go in this competition and we've got to keep the momentum going and put in strong performances.”

Debutants Thailand, who came through qualifying, have now lost both of their games after an opening seven-wicket defeat to the West Indies.

“It was a challenging game for us today, but we tried our best,” said Thai captain Sornnarin Tippoch, who won the toss and opted to bowl.

It couldn't have started better with Amy Jones stumped off the second ball of the day, and when Danielle Wyatt went without scoring the three-time finalists England were reeling at seven for two.

But Knight and Sciver steadied the ship and set about building a big total.

Knight brought up her maiden T20 century off 63 balls, with 13 fours and three big sixes, while Sciver smacked her second successive half-century as the Thai bowlers took a pounding.

Thailand lost opener Nattaya Boochatham in the first over and despite a breezy 32 from Natthakan Chantam were never in the run chase as England restricted them to 78 for seven. Pakistan got their tournament off to an impressive start, beating the West Indies with 10 balls to spare.

“We really wanted this win to get the momentum going into this World Cup,” said skipper Bismah Maroof. “I'm really proud of this bunch and how we played today.

“We picked up wickets at crucial times when we needed and put them under pressure, and then how our openers played, credit to them.” The West Indies won the toss and chose to bat, but slumped to 44 for three off the first 10 overs.

Stafanie Taylor (43) and fellow veteran Shemaine Campbelle (43) came to the rescue - almost tripling the score off the last 10 for a defendable 124 for seven.

In reply, a 58-run opening stand between Javeria Khan (35) and Muneeba Ali (25) set Pakistan on their way, with Maroof, in her 107th T20, seeing them home with an unbeaten 38.