WATCH: Japan concede ridiculous penalty
The 22-year-old capitalised on a failed clearance by the home defenders, rolling the ball into his path and unleashing a powerful shot into the top corner.
Sergej, who has made 26 Serie A appearances for Lazio this season, was unable to stop his side from eventually losing the game, however.
Slovakia ran out 2-1 winners in the friendly meeting, their fourth victory in six outings.
