Marcos Alonso's second-half strike broke Newcastle's resistance as Chelsea moved into the top four in the Premier League with their fifth successive win in all competitions.
The Blues seemed set for another frustrating day at Stamford Bridge after Tammy Abraham saw his header hit the bar and Martin Dubravka denied Christian Pulisic.
But they finally got their reward for relentless second-half pressure when Spanish left-back Alonso drove in a firm, angled shot in the 73rd minute.
They should have scored a second through Abraham, but the England international's shot was brilliantly blocked by DeAndre Yedlin.
Steve Bruce's Magpies were preoccupied with defending for much of the match and failed to test Kepa Arrizabalaga.
Defeat means they drop into the relegation zone, although their manager will point to the fact they have now played every one of the 'big six' in their first nine games, bar Manchester City.
This was the first time Frank Lampard (right) had won five successive matches in his managerial career
Another match and another test passed by Blues manager Frank Lampard.
With only one clean-sheet in 12 games under his tenure, and only five points from their tally of 14 going into the game collected at Stamford Bridge, some had begun to question his side's defending and whether they could handle home pressure.
In the first period the Blues looked off-colour and produced only a couple of half-chances, courtesy of Willian, while England midfielder Ross Barkley limped off injured just before the break.
But in the second half his side looked the embodiment of the spirit of the former Blues midfielder as they persistently tested Newcastle's defence.
After Abraham's header came off the bar and Dubravka had pulled off a wonder-save, they finally made the breakthrough when Alonso found the keeper's bottom left.
It was relief as much as celebration around the ground. The home side should have settled their fans' nerves moments later but Abraham was denied by an excellent stop from Yedlin.
Allan Saint-Maximin (right) joined Newcastle from Nice for £16.5m in the summer
Newcastle are in the bottom three, but this display suggests it is not time to panic just yet.
Once again the Magpies shone defensively, with Dubravka, Yedlin, Fabian Schar and Ciaran Clark leaving everything on the pitch. And perhaps against weaker opposition the effervescent Allan Saint-Maximin will have seen some of his lung-bursting runs have an end result.
The Frenchman is a new fans' favourite on Tyneside and looked most likely to either score for his team or provide an assist. Unfortunately for him and the travelling support, record signing Joelinton was not on the same wavelength in attack.
Bruce threw on forwards Andy Carroll and Dwight Gayle in the last 20 minutes but they failed to make an impact.
Tammy Abraham's aerial threat caused Newcastle the most problems and he was unlucky not to score his 10th of the season
Chelsea manager Frank Lampard, speaking to Match of the Day: "The second half was the most pleasing thing. It was a good test for us today. We changed things a little in the second half and we showed a little more flexibility and creativity.
"We were upbeat, we had urgency, the tempo was good, and that got us the win.
"We want to score goals. You can see the fans - I think they're happy with what they're seeing at the moment. We want more.
"If we want to keep moving up, we can do better. So far this season, though, things are going well."
On Ross Barkley's injury:"It's an ankle injury. We need to assess it and see how bad it is."
Newcastle head coach Steve Bruce, speaking to Match of the Day: "We had a few chances in the first half in particular, but we didn't pick the right pass or the right cross.
"Chelsea have a nice blend of youth and experience at the moment. We didn't weather the storm in the second half.
"We've had a really tough start. We've now got a run of games against teams who are going to be in and around us. Hopefully we can get a few points."
On Chelsea's goal: "I have to say, I thought it was a foul on Joelinton. When you come to Chelsea you need these things to fall for you. I thought it was a clear and obvious foul on Joe."
Chelsea are at Ajax on Wednesday (17:55 BST) in the Champions League before they travel to Burnley next Saturday (17:30 BST). Newcastle host Wolves next Sunday (14:00 BST).