They notched up an impressive 11-0 aggregate win over minnows Barbados but could only draw with Guatemala (67th in the current world rankings).
In all the Americans won eight of their 16 matches, lost four (against Mexico, Honduras and Costa Rica twice) and drew the remaining four.
Until 1 July 2001, the qualification had seemed a formality.
Then a 1-0 defeat by Mexico triggered losses to both Honduras and Costa Rica.
Nerves were finally settled with a game to spare last October when Joe-Max Moore scored twice against Jamaica in a 2-1 win.
Despite their late dip in form and the prospect of group matches against Portugal, South Korea and Poland, coach Bruce Arena is just happy to be heading for the finals.
The 50-year-old, who took charge in October 1998, said: "I think any group would have been fine with us.
"We are certainly pleased to be in the World Cup.
"Portugal are one of the top five teams in the world, so it will be quite difficult to get a point, let alone three points, against them.