Javier Hernandez marked his recall to West Ham's starting XI with a brace as Manuel Pellegrini's men ended Newcastle United's winning run with a 3-0 victory at St James' Park.
After an abysmal start to the season, Newcastle had pulled clear of the Premier League relegation zone with three successive victories against Watford, Bournemouth and Burnley, sneaking above West Ham on goal difference in the process.
However, they were guilty of basic errors at both ends of the pitch on Saturday and were punished as Hernandez - making only his third start of the campaign - scored in either half.
A much-needed win for the Hammers, just their second in seven league matches, became more emphatic when Felipe Anderson added a third in injury time.
Some Newcastle supporters had planned to wait until the 11th minute to enter the stadium, in a protest against Mike Ashley's 11-year reign as owner.
Yet the arrival of those late-comers coincided with the hosts falling behind in sloppy fashion. Kenedy made little effort to prevent Robert Snodgrass crossing from the right and the winger's inswinging delivery was converted by an unmarked Hernandez.
Marko Arnautovic's intelligent movement repeatedly caused problems as Newcastle's defending remained unconvincing, although West Ham were unable to muster another effort on goal in the first half.
In fact, Newcastle should really have been level by the interval, Ayoze Perez guilty of a trio of poor finishes before an excellent Pablo Zabaleta block denied Salomon Rondon on the stroke of half-time.
Hernandez had a golden chance to double his tally in the 58th minute, only to fire into the side-netting following a delightful reverse pass from Felipe Anderson.
The Mexico forward was more clinical six minutes later as he latched on to an Arnautovic flick-on and beat Martin Dubravka at his near post with a precise finish.
Newcastle looked to have been building some momentum prior to that strike, but rarely threatened thereafter and Felipe Anderson made it 3-0 when he took a pass from fit-again substitute Jack Wilshere, rode a challenge from Fabian Schar and nutmegged Dubravka.
What does it mean? Great start to promising month for Hammers
This was the first of seven Premier League matches in December for West Ham and a sizeable points tally will be expected. A run of matches against Cardiff City, Crystal Palace, Fulham, Watford, Southampton and Burnley, in addition to this contest, appears to give Pellegrini's team a real opportunity to climb the table.
Arnautovic a constant threat
Hernandez will get the headlines, but Arnautovic was similarly impressive in attack for West Ham. The Austria international found space time and time again in the first half and was also at the heart of West Ham's best efforts on the counter-attack prior to his 70th-minute withdrawal.
Wasteful Perez fails to deliver
Perez endured a torrid time in front of goal during the first half, initially heading over from a corner when unmarked and then failing to hit the target with his left and right foot. He then made little impression after the break and was replaced by Joselu with 12 minutes remaining.
What’s next?
West Ham will seek to build on this success when they host Cardiff on Tuesday, while Newcastle travel to Everton 24 hours later.
