Carlos Alcaraz lifts Southampton off bottom and has Leicester looking down

In future, Carlos Alcaraz will probably not be celebrating goals with a knee slide. The 20-year-old Argentinian’s first-half goal could prove vital in Southampton’s fight against relegation but in launching himself across the St Mary’s turf, he endangered his part in the dogfight to come.

Victory over Leicester, a team throwing off any pretension of being too good to go down with a dreadful performance, gave Southampton a fighting chance, but they may need a player of such obvious talent. News of his wounded knee will be keenly awaited.

Alcaraz’s goal, created by Che Adams, lifted a game desperately low on quality. It had been low on expectation, too. Both teams were returning to Premier League action after FA Cup defeats to lower-league opposition – Grimsby for Saints, Blackburn for Leicester – categorised as shocking but not entirely surprising.

While Southampton’s slide has taken in the psychodrama of Nathan Jones’ doomed, mercifully short reign, Leicester’s slump has been less heralded. Kicking off three points above the relegation zone, Brendan Rodgers’ standing among the Foxes faithful is diminishing. His team continue to be jarringly over-reliant on James Maddison, who after illness was fit to start. Maddison’s teammates had taken one point from a possible 18 in his post-World Cup absences. There comes a time when injuries and a relative lack of transfer business no longer sustain as viable excuses.

Leaning heavily on star players has been a trait of Rodgers’ managerial career. Maddison’s prominence mirrors that of Luis Suárez and Steven Gerrard at Liverpool and Jamie Vardy earlier in his Leicester reign. Vardy’s star has fallen so far that he was on the subs’ bench, having not started a league match since the 2-2 draw with Brighton on 21 January.

Rubén Sellés, in interim charge of Southampton, gave a first league start since November for England 2006 World Cup squad member Theo Walcott. James Ward-Prowse was playing a record 330th Premier League match for Saints, surpassing Jason Dodd, the coach who nurtured the current club captain’s youth-team days.

Such top-division heritage is as endangered as it has been during Saints’ 11-year tenure and Adams’ return was welcome, adding muscle. Walcott, still just 33 but with a touch of grey in the beard, might have scored early on had Kamaldeen Sulemana not got in the way of his shot.

Much of the first half was forgettable, the home fans as neutered as the action. Kelechi Iheanacho headed a Maddison free-kick wide, and Alcaraz, lively but hot-headed, was booked for a lunge on Timothy Castagne.

Almost from nowhere, Walcott’s burst and cross saw Castagne handle the ball near the touchline. Penalty given. Up stepped Ward-Prowse, only to fluff his lines on his gala day. The Leicester goalkeeper, Danny Ward, much criticised since succeeding Kasper Schmeichel, made a save to his bottom left.

That only served to fire up Saints and after making saves from Alcaraz and Sulemana, Ward could not deny Alcaraz, sent through by Adams’ incisive reverse pass. That Alcaraz’s sliding celebration caused a knee injury looked the brand of rotten luck that befalls a team fighting for its life.

At least Southampton had shown signs of life in a first half from which Leicester increasingly shrank. Alcaraz returned for the second period, his knee strapped, only to pull up after being baulked by Nampalys Mendy and depart soon after, his lesson in over-celebration learned the hard way.

Rodgers removed the disappointing Harvey Barnes for Dennis Praet in search of a foothold. Iheanacho headed wide a decent chance created by Kiernan Dewsbury-Hall’s cross from the left as Leicester began to benefit from Southampton trying to sit on their lead. Such a strategy had been an abject failure in Jones’ final game, against ten-man Wolves, and Hampshire hackles rose as Leicester dominated possession. Alcaraz’s energy was being sorely missed.

Adams and Walcott departed in the 63rd minute, the latter receiving warm applause for his committed performance.

A chorus of boos five minutes later signified Vardy’s arrival. Leicester pushed on, the ball remaining mostly in Southampton’s half, desperate defending the order of the day. Wout Faes headed a Maddison corner wide, Harry Souttar headed against the bar in the dying seconds from Maddison’s cross.

Saints win was seen out, three points gained, though what might be the cost of Alcaraz’s youthful exuberance?