Group A, Bloemfontein: Holland 314-4 (50 overs) beat Namibia 250 (by 64 runs).
Holland sparked wild celebrations from their loyal supporters as they recorded their first ever World Cup victory with a 64-run triumph over Namibia.
Feiko Kloppenburg was deservedly given the man of the match award , after scoring his side's first ever century and collecting four wickets.
Klaas van Noortwijk was also in the runs, recording his country's highest ever score as he finished unbeaten on 134.
Namibia, seeking revenge for defeat at the hands of Holland in the ICC Trophy final, set off positively, with Jan-Berry Burger and Morne Karg ensuring their side kept in touch with the required run rate.
But Kloppenburg, having recovered from his century with the bat, soon returned to haunt the Namibians by removing Burger nine runs short of his half-century.
Karg joined him in the pavilion when his slog off Tim de Leede flew straight to the substitute fielder Nijman.
And as Karg left the field, so Namibia's chances of victory receded dramatically.
Gavin Murgatroyd and Danie Keulder both added half-centuries but as soon as they attempted to accelerate the run-rate, they perished.
With Namibia's hopes of victory dashed, there was still time for Kloppenburg to return and cover himself in more glory.
The all-rounder clinched the wickets of Louis Burger and Gerrie Snyman with successive balls and almost got his hat-trick with a stumping appeal.
Namibia battled manfully, but when Adeel Raja took his fourth wicket, they could only watch as Holland began to celebrate a record-breaking day.
Earlier, Kloppenburg and Van Noortwijk registered Holland's biggest partnership of 228, and the fourth biggest in World Cup history, and took the Dutch to their highest ever total.
Holland suffered an early blow with the news that captain Roland Lefebvre would miss out on a final bow on the international stage with a hamstring injury.
And having won the toss and elected to bat, they were soon on the back foot when Edgar Schiferli edged on to his stumps off the bowling of Rudi van Vuuren.
But after an uncertain start, Kloppenberg overhauled the previous highest total by a Dutch batsman in the 27th over before scrambling a single for his century 10 overs later.
It is such a fantastic feeling to be the first Dutch player to make a century
Van Noortwijk, whose 64 against England in 1995 was the previous highest Dutch score, was not to be outdone and his century came at a much quicker rate.
With the sun beating down in Goodyear Park, both fielders and batsmen struggled with the heat but Namibia gave the score some respectability by grabbing three wickets at the death.
Clearly exhausted, Kloppenburg and Van Noortwijk decided boundaries were the only option and a wild swipe saw the former caught behind by Melt van Schoor.
Louis Burger, Namibia's most economical bowler, also took advantage of some rash play from the Dutch batsmen.
Burger saw off Bas Zuiderent, with Holland's only professional player on five, before removing Tim de Leede with his next ball.
But it was Holland who deservedly had the final say as Van Noortwijk overcame cramp and exhaustion to finish unbeaten on 134.
Holland: Edgar Schiferli, Feiko Kloppenburg, Bas Zuiderent, Daan van Bunge, Tim de Leede, Luuk van Troost (captain), Klaas van Noortwijk, Henk Mol, Jeroen Smits, JJ Esmeijer, Adeel Raja.
Namibia: Jan-Berry Burger, Morne Karg, Danie Keulder, Deon Kotze (captain), Louis Burger, Sarel Burger, Gavin Murgatroyd, Melt van Schoor, Burton van Rooi, Gerrie Snyman, Rudi van Vuuren.
Umpires: Daryl Harper (Aus) and Nadeem Ghauri (Pak)
TV umpire: Darell Hair (Aus)
Match referee: Gundappa Vishwanath (Ind)