Southampton were made to rue missed chances at Anfield, where Liverpool kept alive their faint hopes of playing Champions League football next season.
Sadio Mané nodded in at the back post from Mohamed Salah’s 31st-minute cross – the only time the reigning Premier League champions were able to breach recalled goalkeeper Fraser Forster until Thiago wrapped up the points in stoppage time.
Saints’ best opportunities fell to Ché Adams, twice denied by Alisson, and Nathan Tella, who headed too close to the Brazilian stopper in the first half.
Ralph Hasenhüttl made two changes to his starting line-up, including another switch between the sticks, as Forster replaced Alex McCarthy, having kept a clean sheet in Saints’ 1-0 victory over Liverpool at St Mary’s back in January.
Elsewhere, there was a recall for Everton loanee Theo Walcott on his return to Merseyside, with Takumi Minamino unavailable to face his parent club.
Saints started with purpose, as Kyle Walker-Peters weaved between a couple of red shirts to win a corner, from which Jannik Vestergaard met James Ward-Prowse’s delivery with a glancing blow. Hardly a chance, but enough to offer the visitors some early encouragement.
It would take 10 minutes for Liverpool to worry Saints, as Trent Alexander-Arnold picked out Mané from deep, who escaped Vestergaard but couldn’t keep the bouncing ball down, sending his shot rising into the stand behind Forster’s goal.
Saints looked sharp and were having some joy down the flanks. Tella’s cross towards Adams was just overhit, before Nathan Redmond skipped past Thiago with ease.
Saints had forced three corners by the 15-minute mark, but Liverpool were enjoying the better opportunities, as Mané poked the ball through to Salah in the sort of position you’d expect the net to bulge, but Forster stooped to make an important stop.
Liverpool were beginning to find their groove, and it became apparent midway through the first half that Saints were going to need their goalkeeper to be on top form.
When Mané’s backheel confused the Saints defence, Diogo Jota stole in and skipped his way into a shooting position, but opted for power and struck the ball too close to the giant keeper, rather than picking out the bottom corner.
Then Alexander-Arnold slipped the ball through for Salah, whose first-time curler was parried to safety.
Liverpool were getting closer, never more so than when Georginio Wijnaldum powered a header towards Forster’s top corner, with the keeper for once helpless and grateful to see the ball clip the crossbar on its way over.
When the breakthrough did come, it was a bitter blow for Saints, who had just carved out their best chance of the game at the other end.
Walcott led the charge, feeding Tella down the right, whose cross to Adams was perfect, but goalkeeper Alisson was out sharply and Adams’s attempt to chip the onrushing Brazilian was thwarted.
Even then, indecision between Alexander-Arnold and Thiago offered a second chance, this time for Redmond, but his shot was too close to Alisson, who was still getting back into position.
Saints were punished a matter of seconds later, as Salah crossed from the right and Mané gleefully nodded home at the far post, leaving Forster no chance from six yards.
Hasenhüttl’s men responded with another burst from Walker-Peters, who this time fired across the face of goal.
Liverpool’s problem of late has not been an inability to create chances, rather an inability to take them, and failing to add to a lead has come back to bite them in recent matches against Leeds and Newcastle.
Their desire to score again was plain to see, but Salah took too long to shoot when he darted in behind makeshift left-back Jack Stephens, and Saints retreated in numbers to diffuse the danger.
Liverpool might easily have scored more than once in the first half, but Saints had enjoyed their fair share of opportunities too, including a free header for Tella that was directed straight at Alisson from a position of promise.
Jota tested Forster again early in the second period, trying out the strength of his wrist at his near post with a left-footed whack, but the keeper was up to the task.
At the other end, Saints were looking to release Tella, who was playing alongside Adams, at the earliest opportunity, backing his raw pace against inexperienced centre-back duo Nathaniel Phillips and Rhys Williams, but the final pass, run and touch were never quite in sync.
Tella’s race was run, but the game plan to exploit Liverpool with speed remained in place, as Michael Obafemi filled the void on his return from injury to make just his third appearance of the season and his first in eight months.
Obafemi was instantly involved, motoring on to Adams’s slide-rule pass that exposed Williams, but Alisson came to the defender’s aid, diving at the feet of the substitute.
At the same time that Obafemi entered the fray on 65 minutes, Ibrahima Diallo replaced Walcott, but was soon caught in possession and was indebted to Stephens for bailing him out with a crucial block to deny Salah.
Diallo’s next involvement was far more positive. Obafemi peeled away and nodded the ball down for the midfielder, who connected sweetly on the half-volley to force Alisson into another save, this time tipping the ball over.
Liverpool must have been wondering whether they were about to be hit by a hat-trick of sucker punches, with the game resembling more and more the pattern that led to those recent 1-1 draws.
Next to threaten an equaliser was Adams, who should have punished some more Liverpool carelessness when he picked off a pass out from Alisson, but shot rather tamely down to the keeper’s left, who was able to redeem himself with a comfortable save.
Jota had the chance to kill off Saints from Salah’s cutback but lost his balance as he went to shoot, before Adams was withdrawn for Moussa Djenepo for the final 10 minutes, with the visitors still very much alive.
Try as they might, one last chance would elude Saints, and Thiago eased the tension inside an empty Anfield with a late clincher, caressing the ball into the bottom corner from 20 yards as a brave effort from Hasenhüttl's charges came up short.