"We knew the USA would provide a tough test and they competed hard at every phase,'' said coach Colin Cooper. "They were very physical, very committed and we nearly let them in at the end, but the boys showed plenty of determination to nail the win, so I am really pleased with the overall performance.''
After enjoying a 40-15 win over world No 14 Canada last weekend, the Maori All Blacks may have expected a similar romp against a US team ranked four places below their northern neighbours.
But the Eagles dominated the first half and, when the break arrived with the home side leading 9-7, New Zealand would have been relieved for the respite.
Jamison Gibson-Park had his side off to a good start, taking the ball off the back of a maul and darting across after five minutes, but the US gradually grew into the game. The Americans spent the latter stages of the half camped in New Zealand territory but were unable to come away with anything other than three penalties.
The break disrupted the Eagles' momentum and the tourists started the second spell right on top, with their captain scoring a brace to create some breathing room.
Leading by seven with 15 to play, Bateman showed his respect for the Eagles by opting for a shot from right in front. That proved to be the right move when Cam Dolan burrowed over, though replays appeared to show the No 8 was held up in-goal.
The Americans' hopes for an upset, though, were shattered when Katene ran onto a Robbie Robinson cut-out pass to seal the victory.
"The difference really in the end was the spirit of the team,'' Cooper said. "We used our energy and our culture to come together when it really mattered.''
United States 19 (Dolan try; Siddal 4 pens, con)
NZ Maori 29 (Gibson-Park, Bateman, Bateman. Katene tries; Robinson 3 cons, pen)
HT: 9-7