Football London's Tottenham Hotspur correspondent Alasdair Gold gives us the inside track on Saints' next Premier League opponents...
After back-to-back defeats, how much confidence do Tottenham take from the manner of the draw against Arsenal and the excellent midweek result in Dortmund?
That last 15 minutes or so against Arsenal could end up being crucial for Spurs in the run-in.
Mauricio Pochettino's men looked to be stuttering and stumbling and Harry Kane's spot kick and Hugo Lloris' penalty save gave them a real shot in the arm which they took into their game against Dortmund.
They were excellent in Germany, particularly in their defensive work, and clinical up front through Kane.
Suddenly a season that was spluttering has been reinvigorated again, and injuries aside they'll arrive at Southampton in high spirits and potentially with Dele Alli also back in the squad.
Harry Kane has three goals in four games since returning from injury. Is he looking as sharp as ever?
He looks to be in really good shape. His performance out in Dortmund was a lone striker masterclass in itself, holding the ball up well, spreading the play around the pitch and taking his chance clinically when it came his way.
The last time Kane came back from an ankle injury it took him a long time to look sharp again. Although it sounds crazy bearing in mind he was the World Cup's top scorer, he still didn't look at his best out in Russia long after his return.
It looks like lessons have been learned this time around. Whatever he's changed it's working. It could even be down to Pochettino who didn't use him against Dortmund in the first leg, despite Kane insisting he was ready, which gave him another ten days to ease back in.
Son Heung-Min was on fire whilst Kane was injured. How has the return of the England captain affected Son’s role?
Son enjoyed his time in the spotlight, in fact he revelled in it. He scored in all four of the matches after he returned from the Asian Cup before Kane's own return.
In the four matches since the England captain has come back, Son has retreated into his shell somewhat and the goals have dried up. It's not that they don't know how to play with each other - both have scored many goals together in the side in the past.
It's just been a case of Son adjusting to not being the main man again. He's in a similar role to the one he was playing with Fernando Llorente so that aspect hasn't changed. He hasn't been helped by Christian Eriksen's own dip in form. The Dane pulls the strings for the front men and without him providing the ammunition, Son hasn't had the service he normally has.
What do you expect from Saturday’s game?
It will be interesting to see how Spurs cope without Pochettino in the dugout for the first time since he arrived at the club, unless he appeals his two-game ban.
It's going to be a much tougher game than the one Spurs won back in December and Saints still had their chances that day. Tottenham will have expended a lot of energy in Dortmund and Harry Winks appeared to aggravate his hip problem with half an hour to go. He will be a loss if he misses out.
Southampton have had a full week to prepare and they looked really impressive for long spells against Manchester United. One plus for Spurs is that Alli could be back on the bench and his return will give them another boost after Wednesday's result. Saints have looked so much better on the whole under Ralph Hasenhüttl.
It should be an entertaining match at St Mary's. If Southampton can mimic Burnley's defensive organisation against Tottenham that could be key for them, if they leave themselves open then Spurs will revel in the space.