Bacary Sagna appeared to be fouled under the challenge of Adam Lallana .
The referee allowed play to continue as Roberto Firmino 's low cross came in Eliaquim Mangala got Bacary Sagna 's feet in a tangle and knocked ball past Joe Hart to give the visitors the lead .
Bacary Sagna appeared to be fouled under the challenge of Adam Lallana , but the referee allowed play to continue as Roberto Firmino 's low cross came in Eliaquim Mangala got his feet in a tangle and knocked ball past Joe Hart to give the visitors the lead .