كتب : Amro Hassan
With one league round to go, the big win enforced Sion's position at eighth spot in the table, five ahead of ninth-placed FC Luzern, who earlier lost to Young Boys 5-2.
Sion scored all five goals within the first 52 minutes, before Vadoz hit a consolation six minutes from time.
Egyptian guardian Essam Al-Hadari played the whole of what can be his last game for Sion, as he's set to miss the league's final game due to international duty.
The ex-Ahli man earlier said that this season will be his last with Sion, confirming that he will return to the Egyptian Premier League.
The Vaduz win comes less than a week after Sion sealed the Swiss Cup title with a 3-2 win over Young Boys.