Winston Reid admitted Southampton worked harder than West Ham during Sunday’s defeat at the London Stadium.
The Hammers are enduring their worst start to the season since 2002 – when they were relegated – after slumping to a fifth loss in their opening six matches.
Fingers are being pointed at West Ham’s defending after goals from Charlie Austin, Dusan Tadic and James Ward-Prowse made it 14 conceded in their last four Premier League games.
Defender Reid, who was at fault for Tadic’s goal when he gave the ball away in midfield, told the club website: “When you lose you, you can always do more.
“We’ve played against good teams so far and we need to work a lot harder to get a bit of luck on our side.
“You could see out there that they worked harder than us, and they got a good result.”
West Ham host Middlesbrough next weekend and Reid admits they desperately need a victory to kick-start their season.
“To get our confidence back, we need to work hard,” added the New Zealander. “We need to dig deep and work a lot harder.
“We’re six games in and we’ve only got three points, so we need to dig deeper, produce a better performance and get a win.
“The most important thing for us now is picking up that next three points.”