The 3-1 defeat at Everton means the club have lost five of their opening six matches and, worryingly, have conceded 18 times in the process.
That is easily the worst defensive record in the top flight – Norwich are second worst with five fewer goals shipped – and the third worst in the entire top four divisions.
The only clubs that have conceded more goals are League 2 pair AFC Wimbledon (20) and Oxford United (19) – and they have each played three more league games.
Saints’ defensive fragility was on display on Merseyside during the first half at Goodison Park, as the hosts tore through the visitors with ease at times, running riot in a 13-minute spell that saw them score all three of their goals.
The towering duo of Nikica Jelavic – who twice netted – and Marouane Fellaini were a constant menace, supported by the collective creative spark of Leon Osman, Steven Pienaar and Kevin Mirallas in midfield, as well as marauding full-backs Leighton Baines and Seamus Coleman.
But, while Saints were always likely to be sternly tested against a team that boasted a considerable, not to mention physical, attacking threat, Yoshida insists that they made it too easy for them at times, particularly when defending balls into the box.
“First half was not so good and second half we were a little bit better, but we still need some improvement, especially defensively from the crossing,” said the centre half.
“We made too much mistakes. Too easy to lose the ball in the midfield.
“We have to change these mistakes. Against Arsenal and (Everton) we lose three quick goals and too easy I think.
“In defence we should not change after we lose one goal.
“Offensively, we should keep the ball a little bit more longer.”
Yoshida, who signed towards the end of the transfer window from Dutch side VVV-Venlo, feels there are reasons to be optimistic that Saints will soon tighten up at the back.
In his three Premier League appearances to date, the Japan international has partnered Jose Fonte – a combination that he feels is improving – while he also helped keep a clean sheet alongside Jos Hooiveld in last week’s Capital One Cup victory over Sheffield Wednesday.
“We are improving every minute, every game – game by game,” said Yoshida.
“I am always talking to Jose and Jos as well.
“The combination is getting better. Now I understand how to play with everyone.
“I try and show my performance will get better.”