Defending champions Pakistan were rescued from defeat against Australia by a stirring unbeaten eighth wicket partnership of 65 between Nasir Jamshaid and Ali Asad as three days of warm-up matches ahead of the ICC Under 19 Cricket World Cup in Sri Lanka began on Wednesday.

Meanwhile the beaten finalists in 2004, the West Indies, began their quest to lift the title for the first time with a thumping 87-run win over hosts Sri Lanka which included a hat-trick from pace bowler Kemar Roach.

Zimbabwe recovered from a poor start to comprehensively beat Uganda by 104 runs in an all-African match-up, Ireland overcame Scotland by two wickets in the final over and Nepal were comfortable victors over Namibia, winning by seven wickets with nine balls to spare.

In Moratuwa, Australia's final total of 215 owed most to opener Usman Khawaja who anchored in the innings with 78 but the only other player to pass 30 was Matthew Wade (46) as the 1988 and 2002 winners were bowled out with 3.2 overs of their allocation unused.

Australia's score appeared modest until their bowlers got to work and with left-arm spinner Jon Holland taking 3-53 Pakistan slipped to 151-7 before vice-captain Jamshaid was joined by Ali.

Their unbroken stand occupied only ten overs and Pakistan cruised home with 6.2 overs to spare.

The West Indies have spent the past two weeks in action in Pakistan and their match readiness was in stark contrast to a ring-rusty Sri Lanka.

With William Perkins (53), Richard Ramdeen (52), captain Leon Johnson (51) and Keiron Pollard (53 not out) all making half-centuries, the West Indies powered their way to 293-6, the highest total of the day, with 49 runs coming from the last five overs of their innings.

Sri Lanka were never in the hunt for victory after losing early wickets and they only achieved a degree of respectability thanks to captain Angelo Mathews' 61 and a last wicket stand between himself and Malinga Pushpakamara which produced 60 face-saving runs.

By that stage Roach had taken his hat-trick with the wickets of Dilhan Cooray, Prabudha Perera and Sachith Pathirana and he finished with 4-44 while spinner Sharmarh Brooks captured 3-60 in Sri Lanka's total of 206.

For the home side, all-rounder Mathews did not bowl during the match due to a calf strain.

Ireland almost made a mess of what seemed likely to be a straightforward run-chase against Scotland. With Gareth McKee (65) and Fintan McAllister (58) adding 132 for the first wicket they appeared to be cruising chasing a target of 253 before a late clatter of wickets led to a nerve-jangling finish. Ireland eventually edged home with five balls in hand.

Scotland's total of 252-7 was built around a stand of 95 between Robert Cannon (46) and captain Kasaim Farid (57 not out).

Nepal shocked Namibia, reducing them to 93-5 before Ewald Steenkamp (50) and Henno Prinsloo (57) added 73 to help the Africans to 201-9. Nepal chased down that target in relative comfort with captain Kanishka Chaugai, in his third and final ICC U/19 CWC, top-scoring with 49.

Like Namibia, Zimbabwe made a shaky start, this time against fellow African side Uganda. They slipped to 83-3 and 116-4 before a middle-order revival led by Ryan Higgins (56) and Keegan Meth, who hammered 51 not out from only 24 balls, including three fours and four sixes.

It was enough to take Zimbabwe to an impressive 283-8 which proved well beyond Uganda, although Raymond Otim made an unbeaten 48.

It was a day for wides as virtually all the sides struggled to get used to the swinging white ball. An incredible 192 runs were conceded in wides in the five matches, including 61 runs in one match alone, the Ireland-Scotland encounter.

Uganda and Zimbabwe gave each other 44 runs in wides, there were 42 runs in wides in the Namibia-Nepal match, 27 in the Sri Lanka-West Indies clash and only 18 between Australia and Pakistan.

Further warm-up matches will be played on Thursday and Friday ahead of the official opening of the tournament on Saturday and the first group matches on Sunday.