Manchester City centre-back Eliaquim Mangala is confident the team will resolve their defensive problems before next week's season opener.
City's back line has looked vulnerable during pre-season with Manuel Pellegrini's men losing 4-1 to Real Madrid last month and conceding another four in the first half in Saturday's defeat at Stuttgart.
Defensive frailties were a recurring issue last season and Mangala acknowledges improvement is needed before City begin their 2015-16 Barclays Premier League campaign at West Brom next Monday.
The Frenchman told the club's website, www.mcfc.co.uk: "I think what happened against Madrid and Stuttgart rang one or two alarm bells and maybe showed we have to change something and be aware, because we can't play the way we did in those two games against West Brom or we'll get punished.
"That's why they were valuable games for us, but the fact is that it is better to find out in pre-season friendlies than in the Premier League because the results are not as important.
"It also gives us an idea of the areas we need to work on and improve. Everything is focused on our first game against West Brom and by Monday, we'll be ready and focused."
Mangala had a mixed season after his £42million move from Porto last summer but ended the season well by helping keep four clean sheets in a run of six successive wins.
The 24-year-old said: "I am focused on the season ahead and I want to play my part to the full. I know I need to improve and show my best game every time I play and that's what I intend to do."