Denmark's fast bowlers, led by stand-in captain Amjad Khan, produced an inspired display in the final overs to contain USA to 261 for 9 to set up a four-wicket victory at Severn Cricket Field in Los Angeles. Amjad dedicated the victory to captain Michael Pedersen, who missed the match after flying home on Tuesday night to attend to a family emergency.
USA were 244 for 6 at the end of the 46th over, after being put in, with Timroy Allen on 41 and Elmore Hutchinson - who had just hit two sixes off Aftab Ahmed - on 13. They appeared set for a total of at least 280, especially with the 48th and 50th due to be bowled from the end that produced 10 of their 11 sixes, thanks to the strong wind blowing south down the ground.
However, USA scored a mere 16 off the next three overs, and the big-hitting Allen, who was on 52, only managed a single off the first two balls of the last over. He couldn't regain the strike after that as Aftab strung four successive yorkers, picked up three wickets, and left USA with a below-par total on a flat pitch.
Aftab came out to open the batting as well, and smashed Hutchinson for four and six, either side of being dropped in the first over. Denmark's momentum was briefly halted by Aftab's dismissal in the third over, and the temporary retirement of fellow opener Saif Ahmad, who had injured himself attempting a sharp single. Then Hamid Shah was dismissed for 6 and the score slipped to 54 for 2.
But Zameer Khan and Freddie Klokker put on a 166-run third wicket stand and dominated USA. While seamer Ali Khan and legspinner Timil Patel kept things relatively tight bowling from the North end, the rest struggled, bowling into the wind at the other end.
Denmark also seized on USA captain Steven Taylor's decision to use part-time offspinner Alex Amsterdam for seven overs and restrict specialist left-arm spinner Danial Ahmed to one. It was only a day ago that Danial had tied Oman down admirably, giving away only 29 runs in his 10 overs. He had two catches dropped off him as well.
The partnership was broken in the 40th over - Klokker was bowled for 86, and three more more wickets fell after that - but Zameer saw Denmark through with his unbeaten 97.
Bermuda continued their remarkable turnaround with an 85-run win over Jersey via the Duckworth-Lewis method. They have become outside contenders for promotion despite a poor start to the tournament.
Kamau Leverock and the captain Oliver Pitcher (63) shared a 211-run stand for the first wicket after Bermuda had opted to bat. Leverock struck 137 off 111 balls with 10 fours and eight sixes, including three off three balls off Rhys Palmer's offspin in the 32nd over. The match was reduced to 45 overs after heavy winds blew away the sightscreens in the 15th. Nevertheless, Bermuda recorded the highest total of the tournament, finishing on on 312 for 8.
Then, left-arm seamer Cejay Outerbridge took two wickets at the start of Jersey's chase, and Janeiro Tucker mankaded Will Harris in the 16th over, to reduce the score to 82 for 4. The only resistance came from Corey Bisson, but his 23-ball 48 could not have as much bearing on the match as Outerbridge's 5 for 25.
Oman defeated Italy by five wickets at Wong Cricket Field, chasing down a target of 206 with 9.3 overs to spare.
Italy's top order was wrecked by Rajeshkumar Ranpura and Oman captain Ajay Lalcheta, as they stumbled to 2 for 3 in the sixth over after electing to bat. A 74-run fifth-wicket stand between Italy's captain, Damian Crowley (54), and Carl Sandri (40) steadied them, and an unbeaten 51 from Fida Hussain helped them up to 205.
Sandri then took the new ball, bowling offspin, and removed Zeeshan Maqsood for 0 in the second ball of the chase. It was the Oman opener's second duck in as many days. But Italy couldn't capitalise on the early breakthrough as Arun Poulose (42) and Khawar Ali (30) put on 68 for the second wicket, before Zeeshan Siddiqui hit 54 not out and put on a 63-run stand with Jatinder Singh (29) for the fifth wicket to steer Oman to victory.
The promotion situation
Oman increased their net run-rate during the win, but still trail USA and Denmark on the tiebreak. The loss confirmed Italy as the first team to be relegated to Division Five.
The final day of round-robin play begins on Friday. Oman plays Denmark in Severn, with the winner set to take one of the two promotion berths available. The losing team can still take the second promotion spot but would need USA to also lose to Jersey by a big margin. A win for USA over Jersey would see them promoted.
Bermuda hold a slim chance at claiming the second promotion spot on net run-rate if they beat Italy. But they would be dependent on USA losing, and the Oman-Denmark fixture producing a result by a sizeable margin.
Peter Della Penna is ESPNcricinfo's USA correspondent. @PeterDellaPenna