Despite controlling much of the game, the visitors fell behind in the first half when Takumi Minamino escaped in behind the defence to finish neatly and give Southampton a lead that lasted about 20 minutes.

Mount was lively throughout, inspired against the local rivals of his boyhood team Portsmouth, and won the penalty from which he equalised. Danny Ings was the man at fault, going to ground when a more sensible defender would have stayed on his feet, and there was little reason to argue the decision.

With plenty of time remaining, both sides had chances to snatch a winner. The Saints went closest when Jannik Vestergaard hit the crossbar with a header, with Chelsea’s best opportunity skied over by Reece James. The point leaves us fourth ahead of the remaining weekend fixtures.

Four changes

Edouard Mendy, James, Kurt Zouma and N’Golo Kante were the returning quartet, the latter duo making their first Premier League starts under  Tuchel. Kepa Arrizabalaga, Andreas Christensen, Jorginho and Callum Hudson-Odoi all dropped to the bench as a result.

Tammy Abraham, having been forced off early in the Newcastle victory after sustaining an impact injury to his leg, was deemed fit enough to lead the line up front.

Southampton made two alterations from their 2-1 defeat to Wolves last weekend as both Kyle Walker-Peters and Stuart Armstrong missed out through injury. Former Blues Ryan Bertrand and Oriol Romeu were among the starters for Ralph Hassenhuttl’s men.

Fighting for a way through

Nine places separated the two sides at kick-off as Southampton got things started on a fairly mild but breezy lunchtime by the Solent, with the Saints having failed to win at St Mary’s in the Premier League since their surprise victory against Liverpool a few days into 2021.

Since then, they had lost six consecutive league matches for the first time in their history and more at home to Chelsea in the competition than any other side, all signs that presented an unfavourable outlook for the hosts.

It was almost a perfect Chelsea start as Marcos Alonso, who scored twice on the South Coast against Bournemouth last season, flashed a shot at Alex McCarthy’s goal.

The chance was fashioned with a quick and precise move from the middle to the right, through Timo Werner then Mount and out to James, who picked out his fellow wing-back at the far post. The Spaniard had time to measure the ball’s flight but couldn’t hit the target on the volley.

Saints spring a surprise

That was one of few opportunities in the game’s opening quarter as the Saints’ back-line pushed up high and congested play into central areas. Our deftness of touch or clinical pass was missing in the final third, leading McCarthy to remain largely untroubled. His first save came after half an hour, a routine stop down low from Rudiger, the defender trying his luck from distance more out of hope than expectation.

The Premier League remains one of the toughest competitions because danger is an ever-present reality and Southampton grabbed the breakthrough after 33 minutes with not just their first attempt at goal but practically their first venture into the Blues box.

Moussa Djenepo produced a defence-splitting pass to find Minamino’s run in between Azpilicueta and Zouma, leaving the Japanese international to do the rest with a clever feint to deceive the sliding skipper and onrushing Mendy before a simple finish into the empty net.

New territory under Tuchel

For the first time under our new head coach, Chelsea were behind in a game and required a response. The equaliser almost arrived within minutes after Werner was felled some 30 yards from goal.

Alonso delivered the set-piece, swinging the ball in towards the far post, where Zouma met it with a powerful header that McCarthy pushed around the post for a corner. A VAR check may have intervened for offside, had it been needed.

Tuchel’s first half-time team talk as a trailing manager in English football might have focused on sustaining attacks and building pressure on the home side’s defence, which had been let off lightly in the first period given our dominant possession. The team returned for the restart with a change in personnel, Hudson-Odoi replacing Abraham in attack.

Tide turns with a mistimed tackle

Seaside showers greeted the players for the start of the second half, with the Blues hoping to turn the tide of the contest in the remaining 45 minutes. Our shape was now similar to that deployed at Tottenham, with Hudson-Odoi and Werner operating as split strikers and Mount more central.

Werner was proving a handful down the left with some direct and dangerous running, though his final ball either failed to find a team-mate in the 18-yard box or provide serious work for McCarthy. Nevertheless, Tuchel’s side were soon level as Portsmouth-born Mount restored parity from the spot.

It was the midfielder himself who was brought down in the box following a passage of neat play down the right involving Hudson-Odoi and James. Ings, helping out in his own box, was the guilty party as he upended the 22-year-old with an unnecessary sliding tackle.

Mount did the rest, assuming penalty-taking responsibilities in the absence of Jorginho and rolling the spot-kick to the opposite side of the keeper’s dive to net his second goal in three games. For the boyhood Pompey fan, it was an extra-special moment and his second scoring visit to St Mary’s in as many seasons.

Two points up for grabs

Yet that was not enough for Tuchel, who urged his players to cut short their celebrations and restart the game in search of a winner in the final 36 minutes. All of a sudden, the intensity of the game was different as it balanced precariously on a knife-edge, the risks and rewards heightening with every passing moment.

The contest was not one of many opportunities as two energetic, front-footed teams battled for control and waited for an opposition mistake. A set-piece might decide it and Southampton almost restored an advantage through that route when Vestergaard, who scored a late equaliser in the reverse fixture at Stamford Bridge back in October, took aim with a header.

A recycled corner had found its way back to the Danish defender, who readjusted to stoop low and direct a header towards the far top corner. Mendy and the rest of the Chelsea players could only watch as the ball looped through the air, bounced on to the crossbar and away to safety.

Tuchel tweaks it but win eludes us

Hakim Ziyech and Jorginho were introduced for the final 15 minutes, Hudson-Odoi among those replaced having only entered the fray at the break, but our frustration in front of goal endured.

Mount remained at the heart of all Chelsea’s best play, teasing crosses into the box to no avail. It was he who skipped past Djenepo to reach the byline and find James at the back post with a left-footed cross, his fellow Academy graduate spurning the opportunity.

In the final minutes, the England international hit a rising effort into the stands behind McCarthy’s goal and with that went our last remaining hopes for another Premier League victory.

What’s next?

The Champions League returns for the Blues on Tuesday. Atletico Madrid are our Round of 16 opponents, with the first leg being played in Bucharest. After that, it’s Manchester United at the Bridge next Sunday.

Chelsea (3-4-2-1) Mendy; Azpilicueta (c), Zouma, Rudiger; James, Kante, Kovacic (Jorginho 76), Alonso; Mount, Werner; Abraham (Hudson-Odoi h/t) (Ziyech 76)Unused subs Kepa, Christensen, Chilwell, Emerson, Gilmour, GiroudScorer Mount (pen) 54Booked Alonso 80

Southampton (4-2-3-1) McCarthy; Bednarek, Salisu, Vestergaard, Bertrand; Romeu, Ward-Prowse (c), Djenepo, Minamino (Tella 76), Redmond (N’Lundulu 90+3), Ings (Adams 85)Unused subs Forster, Stephens, Ramsay, Ferry, Jankewitz, ChaukeScorer Minamino 33Booked McCarthy 90+2

Referee Anthony Taylor