In a tense finish, Canada recorded the tournament's first upset victory on its opening day, beating Zimbabwe by 10 runs in their Group C clash at Queen Elizabeth II Park in Christchurch.
Elsewhere, Ireland gave South Africa a few moments of concern before losing by five wickets in Queenstown, but Afghanistan struggled against title holders India, collapsing to 118 all out and going down by eight wickets at the Bert Sutcliffe Oval in Lincoln.
After winning the toss and electing to bat, the Canadians went off at a rate of knots, openers Ruvindu Gunasekera and Hiral Patel rattling up 50 off the first ten overs. But Gunasekera's dismissal triggered a mini-collapse, and at 57 for three Canada were in some trouble as Zimbabwe fought back.
They were rescued by a fine innings from Usman Limbada, who made 90 from 114 deliveries, with six fours and a six, despite regularly losing partners at the other end. By the time he was seventh out in the 48th over the Canadian total had reached 188, and the innings closed on 201 without any further loss.
The wickets were shared among the Zimbabwean bowlers, with Nathan Waller producing an outstanding ten-over spell to take two for 29.
Zimbabwe were soon in trouble when they replied, slumping to 19 for three, but then Dean Mazhawidza and Andrew Lindsay turned things round with a fourth-wicket partnership of 110 in 28.2 overs before Lindsay was caught off Patel's bowling for 40. With 73 required off 16 overs, Zimbabwe now had the upper hand, but the turning point came four overs later when Parth Desai trapped Mazhawidza in front.
The Zimbabwean keeper had made 75 from 118 balls with five boundaries, but with his departure the Canadians were suddenly back in the game. Zain Mahmood removed skipper Dylan Higgins with just six runs added, and Zimbabwe were 150 for six.
The asking rate began to mount as Canada applied the pressure, and as wickets continued to fall the task became steadily more imposing. In the end it was Zain who returned to claim the final wicket with two balls remaining and Zimbabwe still 11 runs short of their target. Limbada took the Man of the Match award for his splendid innings, which undoubtedly set up a remarkable Canadian victory.
Afghanistan's Under-19 World Cup debut saw the Affiliates outclassed by an Indian side which is clearly among the tournament favourites. From the time that skipper Ashok Menaria won the toss and elected to field India had the Afghans under pressure, and once they had been reduced to 38 for five in 21.3 overs there was no mistaking the difference in experience and quality.
Afghan captain Noor-ul-Haq put up some strong resistance, however, making a solid 114-ball 61 and getting his side's total up to 113 before he was ninth man out. Only two other batsmen reached double figures: opener Javed Ahmadi made 19, and Afsar Khan contributed 12 as he helped his skipper add 44 for the sixth wicket in the best partnership of the innings.
There were two wickets each for Saurav Netravalkar, Jaydev Unadkat, Gaurav Jathar and Manan Sharma, while opening bowler Sandeep Sharma conceded only 13 runs in his ten overs and claimed the first wicket to fall.
Aftab Alam made the breakthrough for Afghanistan with the Indian total on 22, but then Lokesh Rahul and Mandeep Singh put on 58 for the second wicket. Rahul fell to a good catch by Ahmadi when trying to work Shir Mohammad Shirzai down through third man, and with Izat Ahmadzai bowling a lively spell at the other end the Afghans fought hard almost to the end.
But Menaria gave Mandeep good support as they knocked off the remaining runs, Mandeep eventually hitting his third six in the 26th over to register his own half-century and take his side to a convincing eight-wicket win; his innings also earned him the Man of the Match award.
In a high-scoring Group D match in Palmerston North, Pakistan held on to break a spirited challenge by the West Indies, who came within 40 runs of an imposing Pakistani total of 297 for seven.
The hero of the day for Pakistan was opener Mohammad Babar, whose 132-ball 129, with 14 fours and a six, was the foundation of their innings; he also took two for 35 and was unsurprisingly Man of the Match. He received fine support from skipper Azeem Ghumman in a third-wicket stand of 124, while Hammad Azam made a rapid 28 not out in the closing stages.
The West Indies were far from over-awed by this total, openers Kraigg Brathwaite and Trevon Griffiths starting off at better than 10 an over and taking just 18 overs for their stand of 120. Griffiths was the main aggressor with 84 off 55 deliveries, but once he was out the West Indian challenge faded.
Brathwaite continued the battle, carrying his bat for a fine 125-ball not-out 92, but no-one could give him the support he needed, and the last wicket fell with the total on 257.