Chelsea would have cemented their grip on fourth place with a win on Tyneside, but they were unable to muster the cutting edge required to break down stubborn Newcastle and fell to Isaac Hayden’s header with just 20 seconds left in stoppage-time, losing 1-0.
Chelsea’s first defeat in four league matches leaves them five points clear of fifth-placed Manchester United.
After four league games without a victory, this was a much-needed success for Newcastle, but a wasted opportunity for Chelsea to open up a bigger gap in the race to qualify for the Champions League.
“We can’t work anymore in training on finishing. You need to have that killer instinct in front of goal. We need to score more goals from front-line areas if we are going to get to where we want to be,” Lampard said.
“It’s quite clear from what I am saying now that we know where we need to strengthen but we shall see.”
At Vicarage Road, Troy Deeney’s 70th-minute spot-kick was saved by Paulo Gazzaniga before Tottenham’s Erik Lamela was denied a last-gasp winner by Ignacio Pussetto’s goal-line clearance.
With England captain Harry Kane sidelined after hamstring surgery, Tottenham has gone three league games without scoring.
Jose Mourinho’s side is without a win in four league matches since December 26 and sits eight points behind Chelsea.
Toothless Tottenham thought they had stolen the points in stoppage-time when Lamela flicked Serge Aurier’s cross towards goal, but Watford’s new signing Pussetto cleared off the line, with goal-line technology showing just 10.04mm of the ball had not gone over.
Arsenal is 10 points adrift of the top four after the Blades continued their superb first season back in the Premier League.
Gabriel Martinelli, 18, broke the deadlock in first-half stoppage-time at the Emirates Stadium with a clinical finish from Bukayo Saka’s cross.
But Chris Wilder’s side snatched the 83rd-minute equalizer when John Fleck lashed home after Arsenal failed to clear.
Bottom of the table Norwich’s vital 1-0 win over fellow strugglers Bournemouth saw the pitchside monitor finally used to decide a red card call.
Norwich took the lead when Bournemouth defender Steve Cook was sent off after flinging himself across the goal to block Teemu Pukki’s shot with his hand.
Pukki fired home the resulting penalty in the 33rd minute, but the Canaries had to survive a tense finish after Ben Godfrey was sent off in the 76th minute.
Godfrey’s foul on Callum Wilson was ruled a red card by referee Paul Tierney after he checked with the monitor, a move that followed advice to officials from Premier League chiefs this week to use the screen more often.
Wolves climbed to sixth after a 3-2 win at Southampton, Everton drew 1-1 at West Ham and Brighton shared a 1-1 draw with Aston Villa.