LONDON: Tottenham Hotspur battled into the FA Cup fifth round with a barely deserved 3-2 win over Southampton on Wednesday as manager Jose Mourinho bemoaned his dwindling options due to the absence of key players.

Already missing long-term injury victims Moussa Sissoko and Harry Kane, plus new signing Steven Bergwijn who was ineligible, the Portuguese had to field France midfielder Tanguy Ndombele who is not yet ready for 90 minutes after a few minor niggles.

Dele Alli was only fit enough for a place on the bench after a late tackle on Sunday by his England team mate Raheem Sterling in Tottenham's 2-0 Premier League win over Manchester City left him nursing a sore ankle, although he did come on after an hour.

But if Mourinho's teams have anything it is the ability to dig out a result against the run of play and his new Spurs side are showing admirable levels of resolve to grind out victories.

After he admitted the best team had lost a thrilling Cup tie at the Tottenham Stadium, Mourinho praised his players for their determination to get themselves out of a hole against a counter-attacking Southampton side who were always dangerous.

Spurs, having led through a Jack Stephens own goal, found themselves behind after strikes by Shane Long and Danny Ings but Lucas Moura and Son Heung-min with a penalty snatched the win.

"We were really in trouble. Lots of fatigue after the match against City. They were better than us, stronger physically, faster than us. They pressed, they had intensity, they had chances. They were the best team," Mourinho told reporters.

"My players were phenomenal. The way they reacted was fantastic. Incredible soul, incredible heart, great connection with the crowd and they gave absolutely everything. So I think the best team lost but we deserved to win."

Mourinho, who said the club's lengthening injury list was making it a difficult season, will grant his players an extra day off after their efforts, although there is no time for the sort of winter break being enjoyed by rival teams.

Midfielder Giovani Lo Celso was missing with a thigh problem and forward Erik Lamela with a groin issue, adding to Mourinho's selection headache but his side rode their luck to reach the fifth round where they have a home tie against Norwich City.