In an extraordinary opening day to the World Twenty20 Qualifier in the United Arab Emirates on Tuesday, Scotland, Kenya and defending joint-champions Ireland suffered shock defeats, which left their chances of qualifying for the main event in the West Indies on a razor-sharp edge.

At the Sheikh Zayed Stadium in Abu Dhabi, the United States of America, who entered the tournament as a wildcard, stunned Scotland by six wickets, while in the afternoon the UAE, who had also been especially invited to participate in the tournament, surprised Kenya by 15 runs.

At Dubai International Stadium in Dubai Sports City, Afghanistan continued their good form, beating Ireland by 13 runs in front of several hundred very vocal supporters, while in the final match of an absorbing day, the Netherlands, who shared the trophy with Ireland when the qualifier was staged in Belfast in 2008, overcame anxious moments to overpower a spirited Canada by six wickets.

After Tuesday's results, all four beaten sides find themselves in must-win situations, while they are also aware of the fact that even if they win their matches on Wednesday, Thursday will be judgement day for them when Ireland go head to head with Scotland in the late afternoon match in Dubai and Kenya take on the Netherlands in the early afternoon match in Abu Dhabi.

Besides all the talk about Thursday, another loss on Wednesday for any of these four teams will mean the end of their hopes to earn a ticket for the Caribbean, where Pakistan will defend their title in the tournament to be staged from 30 April to 16 May.

The USA put up a more disciplined and purposeful performance against third-seed Scotland, which earned them what was a comfortable six-wicket victory. The margin of victory could easily have been eight wickets had they not lost two wickets in three balls when just seven runs were required for victory in 15 balls.

The architects of the USA's victory with five balls to spare were Carl Wright and Lennox Cush, who added 97 runs for the second wicket in 82 balls after Scotland had posted 120 for seven after having won the toss and elected to bat first.

Wright clubbed eight fours in a 57-ball 62, while Cush struck three fours and a six in a 39-ball 41.

Earlier, Scotland's 120 for seven revolved around captain Gavin Hamilton, who top scored with 41 that came off 53 balls and included three fours.

Wright, who was later adjudged Man of the Match, said: "It was a collective effort by us today and a great achievement. The bowlers made it much easier for us to go out and get the runs.

"I'm excited about my man of the match but we have to look to tomorrow, keep up with our positive attitude and move as a group for our game against Ireland."

Hamilton admitted his side needed to win both remaining group matches to progress to the Super Four stage. "I think credit should be given where it is due. The USA bowled well with the new ball and our batting wasn't up to the standard against them.

"Every game is now a must-win. We're going to have a look at the team tonight and we may well have to do a bit of a reshuffle in the side for our game against Afghanistan."

Afghanistan made Ireland pay a heavy price for their sloppy fielding and uncharacteristic batting when they coasted to a comfortable 13-run victory.

Ireland dropped no less than half a dozen catches in the field, then slipped from 52 for one to 78 for five in their 140-run chase and finally failed to finish off the game when they required 16 runs off the last 11 balls with three wickets standing.

For Afghanistan, it was their third recent victory over Ireland after they had earlier beaten undoubtedly the best Associate side in the 50-over format World Cup Qualifier 2009 in South Africa by 22 runs.

Afghanistan must be thankful to Mohammad Nabi, who first struck three fours and two sixes in a rapid 25-ball 43 not out that lifted his side to 139 for eight, and then picked up two for 25 to help Afghanistan dismiss Ireland for 126 with four balls to spare.

However, off-spinner Karim Sadiq was the bowler who broke the back of Ireland's batting when he took two wickets in three balls to finish with figures of three for 21. It was his three-over spell that brought his side back in the game after William Porterfield had looked to be taking the game away from them. Porterfield became one of Sadiq's scalps when he was bowled around his legs after scoring 35 that came off 23 balls and included three fours and two sixes.

Afghanistan coach Kabir Khan was delighted with his side's performance. "It is very heartening to beat a top side like Ireland on a consistent basis. This reflects that we are learning and learning fast.

"It is certainly a jump start for my side as Ireland is the best side in the tournament. The victory has given us a tremendous boost and confidence," he said.

Porterfield was disappointed with the loss. He said: "It is disappointing if you can't chase seven runs an over and are bowled out in 20 overs. There is no doubt that we didn't play well but let's not forget that Afghanistan also played well.

"The equation for us is pretty simple and straight now. We need to win the remaining two matches to progress to the Super Four stage and get our ambitions back on track."

The UAE produced the third upset of the day when they defeated Kenya by 15 runs. Chasing 166 for victory, Kenya, who played the semi-final of the World Cup in 2003 in South Africa, finished at 150 for five.

UAE opener Arfan Haider was the star performer when he belted five fours and two sixes in a 44-ball 59 that propelled the home side to 165 for five. He received good support from Saqib Ali (31), with whom he added 61 runs for the third wicket off 45 balls.

Kenya were never in the hunt after they slumped to 49 for three in eight overs, though Maurice Ouma (39) and Collins Obuya (42 not out) managed to narrow the margin of defeat.

UAE captain Khurram Khan was elated with victory over Kenya. "Everything went right for us today. Batting first, we set ourselves a good target and then bowled and fielded well to restrict Kenya.

"We're very good at Twenty20 cricket and it's something we do well at. It's really a game where two overs can change everything, whether you're batting or bowling."

The Netherlands comfortably chased a 143-run target to beat Canada by six wickets.

Canada lost their star player John Davison in the first over of the match but recovered to reach 142 for seven due to some useful contributions in the middle of the innings, especially from Geoff Barnett, who hit a 20-ball 36 that included six fours.

In turn, a 56-run first-wicket partnership between Alexei Kervezee (39) and Eric Szwarczynski (25) laid the platform on which the Netherlands built their victory. Bas Zuiderent finished as the top-scorer with 43 not out.