The win was much needed for a Santos side struggling in the absence of striker Neymar and playmaker Paulo Henrique Ganso, who are with the Brazilian team at the Olympic Games.
Playing his ninth game since he was promoted to the side by coach Muricy Ramalho in July, Andrade opened his account in the 31st minute when he tapped in Leandrinho's low cross to put Santos 2-1 ahead.
Felipe Anderson, another teenager, had opened the scoring for Santos, while second-half goals from striker Bill and defender Durval completed the win, which lifted Santos to 14th in the 20-team table.
Former Olympique Lyon midfielder Juninho Pernambucano scored a trademark free kick to set Vasco da Gama on the way to a 2-0 win at Sport Recife which took them top of the table.
The 37-year-old, facing his original club for the first time since his return to Brazil last year, curled the ball into the top corner after 21 minutes as he responded to early jeering from home supporters.
Ecuador's Carlos Tenorio pounced on a defensive mistake to round the goalkeeper and score the second as Vasco moved two points clear of Atletico Mineiro at the top, although they have played two games more.
Former CSKA Moscow and Brazil forward Vagner Love scored twice in Flamengo's 2-0 win at Figueirense, their first under new coach Dorival Junior, while Uruguay striker Diego Forlan drew a blank as Internacional were held 0-0 at home by Nautico.