Onmanorama Lite App
Barcelona dominated the match with almost 70 per cent of possession and 18 goal attempts to two for Rayo.
Lewandowski, who scored 344 goals for Bayern in 375 appearances, joined Barcelona in a deal worth 45 million euros earlier this month, after forcing a move from the German club.
Lewandowski, who had 12 months remaining on his Bayern contract, moved to Barcelona in a deal worth 45 million euros and has joined the team on their US pre-season tour.
Spanish media reports that the transfer would cost Barcelona some 50 million euros ($50.4 million).
Results 11-14
