West Ham United boss Sam Allardyce believes that his side's new style of attacking play has cost them their resilience at the back.
Allardyce was told by the club's co-owners David Gold and David Sullivan to produce more attractive football for the new season, following complaints from their supporters during the last campaign.
However, West Ham have struggled to adapt during pre-season as they have lost both of their games on their tour of New Zealand, to the Wellington Phoenix and Sydney FC.
Allardyce told the club's official website: "We're just working on our new style as we've got to get a bit more open and expansive as it seems to be what's demanded in the game now.
"We're working on that side of it but have lost the defensive resilience that saw us get 14 clean sheets last season. The football was not good enough to get results but we're experimenting on playing more open and attacking play.
"We never play our best in pre-season and I don't want the players to play their best in pre-season because I want them to play their best on 16 August against Tottenham."
The Hammers could be without striker Andy Carroll for four months of the campaign as he sustained an ankle ligament injury on the tour.
