Entering week 32, Leicester hold a five-point lead over second-placed Tottenham Hotspur, but that gap could be down to just two by the time that the Foxes take to the field this weekend.
As for Southampton, back-to-back victories have moved them into seventh spot and now just four points off the Champions League positions with seven games of the season left to play in England's top flight.
The finishing line is in sight for Leicester as they chase down what would be the most incredible of title wins in English football, but they simply cannot afford to take their eye off the ball as Tottenham continue their strong challenge at the summit.
A 2-2 draw at home to West Bromwich Albion at the start of March was expected to be the start of a wobble for the Foxes, but they have won their last three in the league without conceding - including a 1-0 success at Crystal Palace last time out.
Much has been made of their form in the final third, with Jamie Vardy and Riyad Mahrez two of the standout players in the Premier League this season, but Claudio Ranieri's side have only conceded twice in their last five league matches and including this fixture, three of their next four in the league are on home soil.
Leicester have won nine of their 15 home league games this season, losing just once, while they have the best away record in the division having recorded 10 victories from their 16 matches on their travels. They are now 16 points clear of fifth-placed West Ham United and even if their title challenge does falter, a spot in the Champions League seems almost certain.
Sunderland (A), West Ham United (H), Swansea (H), Manchester United (A), Everton (H) and Chelsea (A) are what Leicester have to come after this weekend. The last three are particularly tough, but they will hope for a favour from Liverpool, who face Spurs on Saturday, and potentially open up an eight-point lead entering the final six games.
At this stage of the 2014-15 season, Leicester were bottom of the table. They have 41 more points from 31 games this season (66) compared to the previous campaign and a title challenge that was expected to tail off is still going strong. These are the type of fixtures though that will determine whether the Foxes have what it takes to get over the line.
Recent form: LWDWWW
It would be fair to say that it took Southampton a little bit of time to get going this season and while they have had some difficult patches throughout the campaign, they are currently challenging for a European spot as the month of April opens.
Indeed, a total of 47 points has left the Saints in seventh position in the table, just four points behind fourth-placed Manchester City. They lost back-to-back games against Chelsea and Bournemouth at the end of February and start of March, but have beaten Stoke City and Liverpool in their last two to put themselves back in the mix.
After this one, Ronald Koeman's side will welcome Newcastle United, before travelling to Everton and Aston Villa before the end of the month. They then host Manchester City and travel to Tottenham Hotspur, before ending their season at home to Crystal Palace. Like Leicester, it could be a worse fixture list, but there are still some very tricky games for the Saints.
Southampton's away form this season has been a bit hit and miss - winning five, drawing five and losing five of their 15 on the road, while they have only managed 13 league goals away from St Mary's. Ten points have been gathered from their last five away league matches, however, and they have suffered just one defeat during that run.
Koeman's team need 14 points from their remaining seven league games to surpass their points total (60) for last season, when they also finished seventh. They were 10 points off the top four last term, however, and will be keen to make a stronger challenge this time around.
Recent form: WLLDWW
Speaking at his pre-match press conference, Leicester boss Ranieri revealed that "everybody is fit and in good condition" following the international break.
Vardy scored twice for England in their two friendlies, while there were also international debuts for Danny Drinkwater and Frenchman N'Golo Kante, who have both been key to Leicester's title challenge.
A settled XI has been selected throughout the campaign and that is not expected to change this weekend, with Shinji Okazaki keeping his spot in the final third alongside England international Vardy.
Victor Wanyama is also pushing for a recall in central midfield after starting the 3-2 win over Liverpool on the bench, but Shane Long has been described as "doubtful" after picking up an injury while representing the Republic of Ireland.
Leicester possible starting lineup:
Schmeichel; Simpson, Morgan, Huth, Fuchs; Mahrez, Kante, Drinkwater, Albrighton; Vardy, Okazaki
Southampton possible starting lineup:
Forster; Martina, Van Dijk, Fonte, Cedric; Wanyama, Clasie, Davis; Tadic, Pelle, Mane
Head To Head
In total, these two teams have met on 81 occasions in all competitions. Southampton have 31 wins to their name, Leicester 24, while the remaining 26 fixtures have finished all square.
That said, Southampton have not beaten Leicester away from home in the Premier League since December 2001 and have only beaten the Foxes once in their last five attempts.
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We say: Leicester 2-2 Southampton
Southampton will fancy their chances of causing Leicester's back four problems and that could create an open and entertaining game at the King Power. Both teams are full of goals and we are backing a score draw between the Foxes and the Saints this weekend.