Jim Mallinder hailed Saints’ super subs after his side avoided a sizeable slip-up at Worcester.
Northampton recovered from a 7-6 half-time deficit as they ran in three tries during the second half to secure their seventh successive win in all competition.
Samu Manoa, Tom Collins and Tom Wood were all on the scoresheet, with Stephen Myler adding 18 points in a flawless kicking display.
But it took time for Saints to break down a stubborn Worcester side, who have now lost all nine of their Aviva Premiership games this season.
The introduction from the bench of the likes of Tom Mercey, Courtney Lawes and Phil Dowson helped to make the difference.
And Mallinder said: “In the first half our set piece was very good. Our scrum was on top, lineout was good, but we just didn’t bring enough intensity to our game and they defended well.
“We just tried to force it too much instead of just putting the ball behind them and making them turn.
“If we’d scored a try in the first half things might have been a bit different, but we didn’t and they got that chargedown try (through Ignacio Mieres) and their heads were up, which is what they want at half-time.
“Second half, it was pleasing. I think we got a grip on the game, played some good field position and I think the subs did really well when they came on.
“Courtney Lawes was outstanding in getting us over that gain line with a number of carries and that just helped us to up the tempo and to score those tries.”