Southampton manager Ralph Hasenhuttl admits he is focused on tightening up their defence as they are yet to keep a clean sheet.
Saints have conceded four goals in three matches and while they have not been taken apart by any opponent yet, it is an area which requires attention.
Saturday's opponents are free-scoring West Ham, who have found the net 10 times, and Hasenhuttl is aware his side need to be at their defensive best.
"The amount of goals we conceded in the first three games was above the average we try to have so far," said the Saints boss.
"This is what we have to change, this is a tricky topic for the last weeks. It's getting more and more difficult in the Premier League to have clean sheets, you see it every weekend.
"Teams are getting stronger and it's not so easy. A few chances are enough for the opponent to score and this is what makes it so difficult.
"Especially in the last game (a last-gasp 2-2 draw with Newcastle), we normally should've won it and we had the bigger chances.
"Conceding in the end a goal, what is absolutely to defend, and this is what we have to discuss."
West Ham have continued their good form from the end of last season and have taken seven points from nine to sit second in the table.
Southampton have not beaten their London opponents in seven matches and Hasenhuttl is conscious of the threat they pose, with Michail Antonio the Premier League's early leading scorer with four.
"We know the strength that they have: very good individual qualities in the team but also a very clear and efficient way of playing football. This is the reason why they've been so successful," he added.
"They don't give you many chances of winning balls because they don't take many risks building up.
"They have quick counter-attacks, quick ball into the striker and a very dynamic strong guy in Antonio. He can decide games by his own.
"For scoring in the right moments they don't need a lot of chances to score. This is part of a top team."
