Southampton beat Middlesbrough two-one at the Riverside stadium thanks to goals from Jay Rodriguez and Nathan Redmond.
Patrick Bamford's close-range header pulled one back for the hosts, but Saints dug in for three points that moved them level with West Brom with Bournemouth also on 45 points following their win over Burnley.
The opener came through Rodriguez five minutes before the break, with the forward neatly half-volleying Shane Long's cross into Brad Guzan's left corner. Irishman Long's movement made the goal, running from the channel towards the right corner with Jordy Clasie finding his teammate with a cute pass.
It was only Rodriguez's second goal in 19 games, with question marks looming over both his and Long's Southampton careers.
Nathan Redmond added a second ten minutes into the second half moments after Bamford wasted a chance to level the game, slashing onto the roof of the net from close range.
The visitors showed no mercy though, with Rodriguez finding Redmond in acres of space down the left hand side. The Englishman drifted inside the Boro defence before smashing the ball inside the right hand post.
Shane Long earned and missed a penalty just after the hour mark, after being fed in by Ryan Bertrand down the left. He was downed by Guzan who rushed off his line but Long could only blaze his shot onto the bar, lacking composure in front of goal as is so often the case. Redmond then wasted a good chance from a tight angle before Bamford pulled one back for Middlesbrough with 20 minutes remaining.
Substitute Viktor Fischer's curling corner was headed in at close range by Bamford, who did well to meet the ball between Long and Bertrand - it was his first goal in 33 games and Middlesbrough looked as though they might find another for a brief period.
Southampton made a solid, yet unspectacular start to the match playing the patient football that has become their trademark under Claude Puel. The Frenchman chose to rotate for the first time since the busy period at the start of the year, resting Monolo Gabbiadini, Dusan Tadic, Cedric Soares and James Ward-Prowse.
Debuts were handed to Jeremy Pied and Martin Caceres, who impressed apart from one or two rusty moments where the experienced center half was caught on the ball.
One such moment came in the 24th minute, with Adam Clayton gifted the ball by Caseres, with Rodriguez tracking back to prevent Bamford from taking advantage. The resulting free kick, as with several others in the first half, was struck into the wall.
Moments before, Bertrand should have done better at the back post with Long's cross falling to the left back who could only scuff his effort.
Long's goal just before half time looked ominous for the home team, who have for a long time struggled immensely to turn around games once falling behind.
Captain Maya Yoshida was at the center of things late on, giving away a clumsy free kick but being expertly positioned to block Alvaro Negrado's swivel and shot as well as Grant Leadbitter's dangerous cross.
After Charlie Austin returned to action after being injured in December, ex-Saint Calum Chambers forced a smart save from Fraser Forster, rifling a shot through a crowd of players in injury time. The England stopper did well to parry the stinging effort to safety and Saints dug in tor the win.
Rodriguez spurned a late effort that would have seen Saints match West Brom for goal difference after being fed by Steven Davis. The Northern Irishman glided through a couple of Boro defenders and fed his teammate only for him to miss from only a few yards out.
A satisfactory win, Puel rested players for the midweek game against Man Utd but also gave a few others the chance to show why they should be included in Southampton's plans for next season.
Difficult decisions will need to be made this summer, with Puel and his players doing just enough to warrant more time at the club, but little more than that.
Middlesbrough: Guzan, Fabio, Chambers, Gibson (c), Friend, Clayton, Forshaw (Leadbitter 60), De Roon, Downing (Fischer 60), Bamford, Negredo.
Subs: Dimi, Barragan, Bernardo, Leadbitter, Fischer, Traore, Stauni.
Saints: Forster, Pied, Caceres, Yoshida (c), Bertrand, Clasie, Romeu, Hojbjerg (Davis 74), Boufal (Redmond 45), Rodriguez, Long (Austin 87).
Subs: Hassen, Stephens, Targett, Davis, Ward-Prowse, Redmond, Austin.