Scotland 146 for 6 (Coetzer 54, Vala 1-21) beat Papua New Guinea 142 for 9 (Vanua 33, Tahir 3-24) by four runs

Playing their third match in three days in the Dubai heat, Papua New Guinea looked on track to maintain a perfect record at the T20 World Cup Qualifier. But they ran out of gas after Mark Watt's double-strike in the 13th over turned the tide towards their opponents in a dramatic four-win win for Scotland on Monday.

Chasing a target of 147, PNG were 81 for 2 in 12 overs before Watt's intervention. After he had been driven for two sixes in the opening over of the chase by Assad Vala, Watt bounced back with a maiden in the sixth before an over that won the match for Scotland, at least according to PNG captain Vala and Scotland stand-in captain Richie Berrington - Kyle Coetzer didn't take the field after his first-innings fifty due to dehydration. Charles Amini drove the second ball to Calum MacLeod at long-off for 9 before Lega Siaka was bowled on an attempted drive next ball for 31.

Fellow left-arm spinner Hamza Tahir built off the Watt breakthroughs with two more wickets of his own in the 15th, bowling Riley Hekuru playing over the top of a pull before Sese Bau slogged a short ball to sub fielder Michael Leask at deep midwicket to make it 94 for 6.

PNG never stopped fighting though allrounder Norman Vanua rallied on. With 26 needed off two overs, Jason Kila pulled Safyaan Sharif for back-to-back fours before Vanua clubbed a full toss for six over long-on, his second of the innings, to take the target down to nine off the last over. But Josh Davey was immaculate at the death. Kila pulled the first ball to George Munsey at deep midwicket before Vanua couldn't get enough power behind a lofted drive taken by Tom Sole at long-on. The last-wicket pair of Nosaina Pokana and Damien Ravu could only manage four off the last four balls.

Coetzer had anchored Scotland's innings grinding his way to a 42-ball half-century in the stifling heat. Outside of Munsey's assault on Bau's offspin in the second over - twin reverse sweeps for four and six - Coetzer didn't get much support during the innings. Munsey fell in the fourth to a skied drive to mid-off before Vanua trapped MacLeod for a four-ball duck in the next over, putting pressure back on Scotland in the Powerplay.

Coetzer found his release shots slogging a pair of sixes over long-on to push Scotland forward. He finally fell in the 17th, slogging Amini's legspin flat to Pokana at long-off. Matthew Cross then provided a crucial late burst, striking a six and four fours across the final four overs, to get Scotland up to a total that proved to be just enough in the end.

Peter Della Penna is ESPNcricinfo's USA correspondent @PeterDellaPenna