Barcelona were matched at 1.04 on Betfair to beat Arsenal after a footballing masterclass at Emirates Stadium.
Pep Guardiola's brilliant European champions dominated but over £200,000 was lost as the Gunners hit back with a late double few could have predicted.
The draw was backed as big as 28/1 and the final score of 2-2 was traded at a high of 48.
Barca are inevitably strong favouriters to progress.
The Catalan side can be backed at 1.21 with Arsenal, who are without Cesc Fabregas, available at 5.3.
