Newcastle was among the top spenders in Europe in the winter transfer window in a last-gasp bid to escape relegation from the lucrative Premier League.
Its $42 million splurge had little effect at Everton on Tuesday.
Newcastle started three of its new signings at Goodison Park and was beaten 3-0 to stay third from bottom in the standings, two points from safety.
Ross Barkley converted two late penalties - one of them a so-called "Panenka" down the middle - to add to the opening goal from winger Aaron Lennon, as Everton collected a first league win since 26 Dec.
In the only other Premier League match this evening, sustained late pressure failed to yield a goal for Chelsea in a 0-0 draw at Watford, which kept the champions unbeaten in nine games in the interim spell of coach Guus Hiddink, but in 13th place - 11 points off the European positions.
Chelsea was sparked into life by the introduction of Eden Hazard from the bench in the 73rd minute, but couldn't find a way past Watford goalkeeper Heurelho Gomes, who saved well from Branislav Ivanovic and Diego Costa.
Newcastle coach Steve McClaren would have been banking on an improvement after splashing out last month on Jonjo Shelvey, Henri Saivet and Andros Townsend, who all started against Everton in a revamped midfield.
Yet, his side was lucky to escape a bigger beating, with Everton also hitting the goal frame on three occasions.
"We just went back to what we were three or four months ago," said McClaren. "It wasn't acceptable."
Newcastle has taken just five points from eight matches since their last league victory, at Tottenham on 13 Dec.
Lennon put Everton ahead in the 23rd minute, swiveling just inside the area after collecting Tom Cleverley's pass and placing a low shot inside the post.
Barkley, playing in his 100th league game, was one of the players to be denied by the goal frame, but secured victory for Everton from the penalty spot in the 88th after Lennon was fouled. The England midfielder converted another spot kick in injury time, dinking the ball home after he was tripped by Jamaal Lascelles.
The substitute was sent off for the foul.
"Phenomenal footballer, phenomenal person," Everton manager Roberto Martinez said of Barkley. "He took responsibility with both penalties and showed how he is an assured, technical footballer."