Foden charged through late on for a Northampton try
Second-half tries from Chris Ashton, Ben Foden and Phil Dowson helped Northampton move up to second and pile more misery on struggling Worcester.
The home side enjoyed more possession in the first half but failed to capitalise and they were made to pay.
Ashton crossed just after the hour mark for his eighth try of the Premiership season after being set up by Foden.
Foden then went over five minutes from time and Dowson made it safe but Saints just missed out on a bonus point.
Three penalties in the opening 23 minutes by Stephen Myler put the visitors in control with Myler kicking his third after lock Craig Gillies was sin-binned for taking out the man without the ball.
Despite being reduced to 14 men for 10 minutes by Gillies' sin-binning, Worcester continued to play with purpose and they trimmed the lead by three points when Saints were caught killing the ball in a ruck and Walker kicked the penalty.
Walker missed two further penalty attempts and although he was successful with one just before the break, he was replaced by former Wales fly-half Matt Jones, who made his first Premiership appearance of the season following his recovery from a broken foot.
Jones's attempted drop goal drifted wide and it proved costly when Miles Benjamin fumbled Johnny Arr's box kick and Foden scorched through a ponderous defence before he off-loaded to Ashton who went over under the posts with Myler converting.
Foden then used his strength to batter through after a period of forward pressure and Dowson embellished victory with a late third try to give his side their eighth consecutive win in all competitions.
Worcester director of rugby Mike Ruddock:
"We were in the 22 for quite a long time in the first half, and had loads of chances but didn't always convert them.
"We didn't nail our golden periods where we had field position and pressure. When Northampton had periods of field position and pressure they scored every time.
"It was all on a knife edge and I thought we had a good chance to win the game, but Willie Walker missed a penalty attempt and Matt Jones missed a drop-goal option. Those little margins that could have pushed us into pressurising Northampton didn't go for us."
Northampton director of rugby Jim Mallinder:
"We started strongly and were nine points up and controlled the game well. We then made a lot of mistakes in the second period of the first half and let Worcester back into the game.
"But we put the pressure on in the second half. Our scrum got stronger in the second half, it was a good performance at the line-out where we took a lot of their ball.
"I think Worcester also tired, and when teams tire against us we have got the players in our side who always have the chance of scoring."
Worcester: Latham; Gear, Grove, Tuitupou, Benjamin; Walker, Arr; A Black, Lutui, Taumoepeau, Rawlinson, Gillies, Wood, Sanderson, Horstmann.
Replacements: Rasmussen for Tuitupou (70), Jones for Walker (55), Mullan for A. Black (55), Fortey for Lutui (77), Kitchener for Rawlinson (55).
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