In the final centre court match of the day, 18-year-old young gun Denis Shapovalov blasted past Brazilian Rogerio Dutra Silva in a 6-3 6-2 win.
The duo entertained an Auckland crowd disappointed by Michael Venus' quick exit as they both went for clean winners, but it was Shapovalov who showed why he is attracting so much hype as a future star.
Wielding his eye-catching one-handed backhand, the Canadian slashed winners down the line and across court while also powering a 216km/h ace past the Brazilian.
Roberto Bautista Agut's and Shapovalov's safe progression into the second round ensured the Classic's more fancied players all made it through on the opening day.
This included popular four-time Classic champion David Ferrer, who harnessed all his experience to weather a storm from Chinese young gun Yibing Wu to win 7-6 (9-7) 6-4.
Last year's runner-up, Portugal's Joao Sousa, also survived a scare to knock American Donald Young out of the tournament 6-7 (10-8) 6-4 6-2, while rising Russian star Karen Khachanov progressed in three sets.
Twenty-one-year-old Khachanov beat Japanese journeyman Yuichi Sugita 6-1 3-6 6-4.
Earlier on Monday, Russian eighth seed Andrey Rublev and British world No.49 Kyle Edmund withdrew with injuries.
They have been replaced by two lucky losers, Slovakian Lukas Lacko and American Tennys Sandgren.