Not many people have been tipping the Saints for relegation due to the improvement they have made under Ralph Hasenhuttl over recent months, but Saturday's 3-1 loss at Newcastle does leave them still looking over their shoulders, as they are just five points clear of the drop zone.
One more win should be enough to get Southampton over the line in terms of survival and they do have a good recent record at Vicarage Road, as they are unbeaten on their last five visits to the venue.
However, Watford are a different beast under Javi Gracia this season and they will move back up to seventh in the standings as long as they avoid defeat on Tuesday.
The Hornets have only lost one of their last six home games in the league and there have been no signs of them taking the foot off the gas, even though they will have one eye on next month's FA Cup final against Manchester City.
Gerard Deulofeu has been the man in form for Watford of late, with four goals from his last two starts, and he is likely to be the Hornets main threat on Tuesday, particularly as Troy Deeney will be serving the second match of his three-game ban.
Roberto Pereyra could also miss out for Watford as he continues to struggle with the hip injury that saw him miss Saturday's 2-1 win at Huddersfield.
Mario Lemina made a goalscoring return as a substitute for Southampton on Saturday and he will now be hoping to earn his first start since December.
Defender Jannik Vestergaard could also feature after missing the defeat on Tyneside due to a minor knock.