The Blues will make the trip to the south coast looking to secure their first Premier League win since a 2-1 win against Crystal Palace at Stamford Bridge on 10 March.
Chelsea FC are in fifth place in the Premier League table and 10 points behind Liverpool FC and Tottenham Hotspur in the race to secure a Champions League spot.
The west London outfit are facing the real possibility of a season without Champions League football despite winning the Premier League title with two games to spare last term.
The defending Premier League champions will have a dress rehearsal for their FA Cup semi-final against Southampton at Wembley later this month.
Former Arsenal midfielder Merson is tipping Chelsea FC to ease to a resounding 3-1 win against Southampton at St Mary’s on Saturday afternoon.
“This is a must-win game for Southampton. Would they rather win this or the FA Cup semi-final next week?” Merson told Sky Sports. “I don’t know.
“I think Southampton need to have a go and that will allow Chelsea to pick them off.
“It’s a nice game for Chelsea as Southampton have to come out and play and aren’t going to kick them off the pitch. I don’t think they will make it that hard for Chelsea.
“Southampton had a great chance to beat Arsenal last weekend after taking the lead but if they don’t win this game then they probably need to win two or three of their last five, which is too much.”
Chelsea FC haven’t won the Champions League since 2012 and the Blues lost 4-1 aggregate loss to La Liga giants FC Barcelona in the round of 16.
The Blues have won the Premier League title in two of the past three seasons.
Chelsea FC signed Ross Barkley, Emerson Palmieri and Olivier Giroud in January.
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