Adam Armstrong's double fired Southampton to a 2-0 victory over Cardiff and to Saints' longest unbeaten run for 29 seasons.
Armstrong curled and headed in his 11th and 12th goals of the season to stay on the heels of Blackburn's Sammie Szmodics in the race for the Sky Bet Championship's Golden Boot.
Saints stay fourth but the 11 matches they are now without defeat has equalled the number they went unbeaten between December 1994 and February 1995 - though that run remarkably contained nine draws, in contrast to the eight wins in the current sequence.
The opener came in the 11th minute to complete a fine team move.
Saints had passed and moved their way down the left flank before Flynn Downes fired in to Carlos Alcaraz, who laid off to Adam Armstrong. The in-form hitman took a touch before bending into the top corner.
Four minutes later the same player doubled the hosts' lead. This time it was Stuart Armstrong's quick feet that earned space on the left side of the box before his cross deflected up off Dimitrios Goutas and onto Adam Armstrong's head.
While chances did not come freely for Southampton, they kept the ball and toyed with the Bluebirds with incisive passes as freezing fog hovered over St Mary's.
Adam Armstrong almost completed his hat-trick when Che Adams' cross was pawed into him but his header lacked power and allowed Alex Runarsson to scramble back across his line to hold on.
Alcaraz headed over a Stuart Armstrong centre but the third goal should have gone to the visitors in first-half stoppage time. Perry Ng's deflected ball into the box found Josh Bowler a couple of yards out and free at the back post, but he skied over the crossbar.
Cardiff had only been behind once before at the break this season, and continued their attempt to a comeback as Karlan Grant fired wide.
Che Adams replied in kind in his first start since October before substitute Joe Aribo squirted a shot against the base of the post.
Ryan Fraser had three good chances to put Saints clear but failed to put either on target before a third effort was deflected wide.
The hosts continued to slice through hapless Cardiff but Runarsson denied Adam Armstrong a third after a rasping drive.
Fraser continued to be frustrated in front of goal while Sekou Mara also had shots as Southampton could have justifiably won by a landslide.
Former Swansea boss Russell Martin continued his 100 per cent win record against Cardiff but saw their promotion position unmoved, with Leicester, Ipswich and Leeds also winning.
Southampton: Bazunu, Walker-Peters, Manning, Downes, A. Armstrong, C. Adams (Mara 81'), S. Armstrong (Aribo 62'), Harwood-Bellis, Alcatraz (Fraser 62'), Charles, Bednarek. Subs Not Used: Lumley, Holgate, Bree, Edozie, Amo-Ameyaw, Dibling.
Cardiff City: Rúnarsson, Ng, Goutas, McGuinness, Collins, Wintle, Siopis (Ralls 75'), Robinson (R.Colwill 55'), Bowler (Tanner 62'), Grant (Etete 75'), Méïté (Ugbo 62'). Subs Not Used: Alnwick, Romeo, Panzo, E. Adams.