Robert Lewandowski struck twice for Hansi Flick's Barcelona to deliver a battling 2-1 win at Valencia in their La Liga opener on Saturday. The German coach celebrated his first competitive match at the helm with three points as Barca came from behind against Ruben Baraja's solid Valencia side. Hugo Duro sent the hosts ahead after 44 minutes but veteran Polish striker Lewandowski levelled from close range before the break and netted a penalty early in the second half. With champions Real Madrid, led by new superstar Kylian Mbappe, in action on Sunday at Real Mallorca, Barcelona started their bid to steal the crown with an impressive result at Valencia's rowdy Mestalla stadium.