Nagamura tied it in the 87th minute, finishing Chance Myers' cross with a laser from behind the area. Nagamura then finished Soni Mustivar's cross with a glancing header in the fourth minute of stoppage time. The final whistle came shortly after the ensuing kickoff.
Dom Dwyer scored on a header in the 81st minute to cut Sporting's deficit to 3-2. It was his eighth goal of the season.
Pedro Morales' 25-yard free kick gave Vancouver (13-9-3) a 3-1 lead in the 75th minute. It was the Whitecaps' second two-goal lead of the evening. Kekuta Manneh capitalized on Sporting giveaways for a pair of first-half goals for Vancouver.
Kevin Ellis pulled Sporting (11-4-7) to 2-1, scoring an opportunistic header in the 53rd minute.