The Blues have lost just once in their last 14 games, and are unbeaten in the Barclays Premier League since Guus Hiddink replaced José Mourinho as manager in December.
Saints are in good form themselves, of course, having not so much as conceded a goal since mid-January – a run that has taken Koeman’s men in sixth in the table.
Nevertheless, the Southampton manager is anticipating a big test of resilience at St Mary’s this weekend given Chelsea’s resurgence from their poor start to the campaign.
“They had a very difficult start to the season but they are now coming back, which I think is normal because they have good players,” Koeman told youtube.com/southamptonfc
on Thursday afternoon.
“They have a strong team, and it looks a little more comfortable and convinced in what they are showing in the last few weeks. They had a great FA Cup result against Man City (a 5-1 win last Saturday), which has given everybody a boost in confidence.
“We haven't lost against Chelsea until now [since Koeman took over], but we know it's a difficult opponent so we need to be strong.
“We need to be at our strongest to have a chance in the game. It's difficult to beat Southampton, they know that, but we need to be at our best to have a good result this Saturday.”