Cricketing minnows Oman pulled off a massive upset by beating Ireland by five wickets in their opening World Cup qualifier in Bulawayo on Monday, the Gulf sultanate's first-ever victory over a Test nation in an ODI. 

The other Group B match saw Sri Lanka crush the United Arab Emirates by 175 runs.

ALSO READ: Najam Sethi withdraws candidacy, Zaka Ashraf set to return as PCB chairman

George Dockrell hit 91 not out and Harry Tector 52 as Ireland reached a respectful 281 for seven wickets in their allotted 50 overs.

But they hadn't counted on the fighting qualities of an Omani side for whom opener Kashyap Prajapati hit 72, while skipper Zeeshan Maqsood pitched in with 59, Aqib Ilyas 52 and Mohammad Nadeem 46 not out.

A triumphant Maqsood said it was an "honour" to have beaten Ireland, eventually by five wickets with 11 balls remaining.

"If we continue like this, some more results will be in our favour. It was a collective and combined performance, which we need to beat a good side. We came here to go there (to India) and play."

Ireland captain Andy Balbirnie called the defeat "very disappointing".

"We felt like we had a pretty good score," he said. "280 in a one-day game is pretty good. They were hard to bowl to at times. We felt right in the game.

"Oman's win didn't take us by surprise... it's a long tournament. We need to get back into it pretty quickly."

The second Group B game was much more academic, Sri Lanka racking up a massive 355 for six wickets off their 50 overs.

There were four half-centuries thanks to Kusal Mendis (78), Sadeera Samarawickrama (73), Pathum Nissanka (57) and Dimuth Karunaratne (52), while Charith Asalanka chipped in with 48 not out.

The UAE were in the chase for the first 30 overs, but the tail collapsed, the last five wickets falling for just 13 runs.

Wanindu Hasaranga claimed a first ODI five-wicket haul with 6-24 off eight overs as Sri Lanka bowled the UAE out for 180.

"We know he is going to do the job always," Sri Lanka captain Dasun Shanaka said of Hasaranga.

"We've been playing well in the recent past. Playing qualifiers is always special but we don't take pressure when we play cricket."

The action continues Tuesday, with hosts Zimbabwe facing the Netherlands and Nepal taking on the United States in the second round of Group A matches at Harare.

Only two of the 10 teams taking part in the three-week qualifier will make the World Cup to be played in India in October and November.