Boss Jos Luhukay admits Sheffield Wednesday must improve their defending as they head towards next Saturday's Championship opening-day clash at Wigan Athletic.
The manager watched the Owls concede soft goals as they lost to leading Spanish side Villarreal 3-1 at Hillsborough this afternoon in their final dress rehearsal before the league action begins on August 4.
Classy Villarreal, who finished fifth in La Liga last season, sealed victory with a superbly-worked third strike, but both of their earlier efforts could have been avoided.
"We have one week to do it better," Luhukay said.
Wednesday began with Joe Wildsmith in the net with a back three of Joost van Aken, Tom Lees and Daniel Pudil and finished with Cameron Dawson as goalkeeper and a defence of Frederick Nielsen, Jordan Thorniley and Pudil.
Keeper Keiren Westwood, a transfer target for Stoke City, didn't make the squad.
After the visitors led 1-0 through Pudil's headed own goal, Liam Palmer's excellent effort levelled the scores before the break, but the Spanish outfit eased clear through a Ramiro Funes Mori's free header and a lovely dinked finish by Karl Toko Ekambi.
The Owls' defence was opened up too easily throughout the game.
"We had very good opponents in Villarreal," Luhukay said. "I am pleased we can learn from the technical quality they have. We had a couple of good periods in the first half."
Luhukay welcomed the return of striker Steven Fletcher who came close to scoring in the second period as he made his comeback following a long lay-off with a knee injury.
"It was very important today that the players got minutes," the boss said. "Steven had two or three good moments to score."