West Brom 0 Southampton 1 - Report and pictures
[gallery] Albion failed to score for the third game in a row as Jordy Clasie's tidy first-half strike closed the gap between ninth and eighth to four points.
The Dutch midfielder rippled the net from the edge of the area in the 25th minute to win a tight encounter between two safe mid-table teams.
The Baggies started the game on top, and enjoyed plenty of possession in Southampton's half with James Morrison stinging Fraser Forster's palms from range and Nacer Chadli looking threatening.
But it was the visitors who took the lead. Shane Long was afforded too much time in the final third, and the former Baggie burst into the box before squaring to Dusan Tadic.
He held the ball up before laying it off to Clasie, who rippled the corner of the net with his first-time shot with Ben Foster rooted.
Saints might have doubled that lead shortly before half-time when Tadic robbed Darren Fletcher in midfield and sent Long clear, but he looked for a challenge from Evans that never came.
He fell to the floor and immediately got back up when he realised there was no touch, but by then the chance had gone and the Baggies were breaking up the other end where Rondon's header back across goal had to be palmed clear by Forster.
Pulis made three changes early in the second half and switched to two up front in an effort to force the issue, and the game started to open up.
Chadli had a shot straight at Forster after good work from James McClean and Hal Robson-Kanu, while Redmond was testing Foster's reflexes up the other end.
But Albion's best chance fell to defender Craig Dawson in injury time after Jake Livermore lifted the ball into him, but Forster parried his volley before Allan Nyom blazed the rebound earlier.
There was still time for Evans to divert a corner goalwards late on, but Forster tipped over his effort to ensure the Baggies endured back-to-back defeats in the space five days.
Analysis
Super Bob Taylor was interviewed at half-time after cycling from Southampton to The Hawthorns over the past few days to raise money for The Albion Foundation.
Oh what the Baggies would do now for an accomplished finisher like him.
Albion haven't scored in any of their last three games, but more worryingly, their two strikers have only netted two goals in the last 16 league games. Both of those have been scored by Hal Robson-Kanu.
Salomon Rondon was reinstated to the line-up today, and he worked his socks off, but his main threat will always be in the air.
In the second half, the giant Fraser Forster punched the majority of aerial missiles sent his way from messrs McClean and Brunt.
Meanwhile, Southampton stood firm to Albion's carpet schemers like Chadli and Morrison.
Albion have been brilliant at The Hawthorns this season, and they started the day with eight wins from their previous 10 home league games.
But the majority of those wins have been built on destructive counter-attacking football.
When they're required to break down defences, that's when they struggle. Today, it was Southampton who swept up the pitch with purpose while the Baggies, without playing poorly, rarely found their rhythm.
Pulis made three changes to his team bringing in Rondon, James Morrison and Matt Phillips for Robson-Kanu, Chris Brunt, and James McClean.
The three players reinstated to the line-up were in the thick of the action straight away, as Southampton started the game sloppily.
The Saints were misplacing passes and backing off Albion at an alarming pace but it wasn't clicking for the home side.
Rondon miscontrolled Phillips's cross-shot when he was free at the back post, but his blushes were spared by the linesman's flag.
Nacer Chadli embarked on a mazy dribble into the box before getting crowded out and then Morrison tested Fraser Forster with a drilled long-range effort with his left foot.
Which is why Southampton's goal was somewhat against the run of play.
Clasie's first-time finish was a tidy one, but Albion's defence looked disinterested in the build-up, when they gave Long far too much time in the final third to turn and run into the box.
The former Baggies man should have been booked shortly before half-time when he fell to his knees expecting a touch from Jonny Evans that never arrived, and his immediate return to his feet without protest gave away his guilt.
But that chance came about because Fletcher was robbed in midfield. After the goal, Southampton looked sharper while all the early confidence eight wins in 10 home league games had built up seemed to drain out of the Baggies.
Pulis made an early change, sending Chris Brunt on for Gareth McAuley and putting him left-back while moving Nyom over to the right and shifting Dawson inside.
And Brunt was obviously ordered to overlap as much as possible, because his first contribution was a burst up the wing followed by a cross to Rondon at the back post, but the Venezuelan's header back across goal was gathered by Forster.
After that Pulis really went for it, sending Robson-Kanu on for ever-present skipper Fletcher and switching to two up front.
It nearly worked, and when the Wales international, who has been impressive with his back to goal recently, laid the ball off to Chadli following McClean's burst into the box, it felt like the moment. But the Belgian's shot was straight at Forster.
Robson-Kanu scored a thunderous winner against Southampton at St Mary's on New Year's Eve, and he was nearly the hero again when Forster flapped a cross to his feet, but the keeper did enough to put him off and he skied his effort.
Whatever the result, this mid-table clash will likely be last on Match of The Day tonight. Neither team will go down, and neither will qualify for Europe, but there was still plenty riding on it.
Southampton started the day seven points behind the Baggies but with two games in hand. Now they are just four points behind and they smell blood.
Albion are still in pole position, and you would rather have the points on the board, but the next two matches are tricky fixtures against Liverpool and Leicester.
There are still six games to go, but the chances to pick up the two victories needed to reach 50 points for the first time in the Premier League era are dwindling fast.
Key moments
25 GOAL SOUTHAMPTON - Long is afforded far too much time on the ball and he finds Tadic in the box. He lays the ball off to Jordy Clasie, who ripples the net from the edge of the area.
Man of the match
Fraser Forster - Made six saves, including two late on to earn his side the points
Position in the table
8th, with 44 points from 32 games.
Teams
Albion (4-1-4-1): Foster, Dawson, McAuley (Brunt 53), Evans, Nyom, Livermore, Chadli, Fletcher (c) (Robson-Kanu 66), Morrison, Phillips (McClean 61), Rondon. Unused subs: Myhill, M Wilson, Yacob, Field.
Southampton (4-2-3-1): Forster, Soares, Yoshida (c), Stephens, Bertrand, Clasie (Reed 84), Hojbjerg, Ward-Prowse (McQueen 71), Tadic, Redmond (Sims 71), Long. Unused subs: Hassen, Caceres, Pied, Rodriguez.
Referee: Chris Kavanagh (Manchester)
Attendance: 24,697 (2,289 away)