With the win, the Railroaders tied Truckee for the best record in the Mount Rose League, but the Wolverines received the top seed via tiebreaker rules.
Against Whittell, Hector Hernandez started the scoring in the 32nd minute off an assist by Jose Mendoza.
Sparks went up 2-0 seven minutes later when Kevin Partida drilled home a free kick.
In the 45th minute, Oscar Gomez was fouled in the box. Ruben Pacheco stepped up and knocked home the penalty kick for a 3-0 edge.
Whittell scored its lone goal in the 68th minute.
Sparks improved to 23-1 overall and 15-1 in league and will host Elko in the first round of the playoffs at 3 p.m. Wednesday.