Talks were scheduled between Stamford Bridge officials and Ba's representatives last night. A clause in Ba's contract means Alan Pardew is powerless to prevent the 27-year-old's departure from St James' Park and it is understood Chelsea are also willing to pay a further £2m in agents' fees to get the deal done.
Having agreed the £12m sale of Daniel Sturridge to Liverpool, Benitez needs more firepower because he saw Fernando Torres toil again despite an encouraging victory at Goodison Park.
Benitez was tight-lipped on the potential new arrival. "We do not talk about our business in public," he said. "Ba plays for another team so I do not like to talk about it."
Newcastle United are resigned to losing Ba who is looking for a five-year contract and wages of around £83,000-a-week.
Ba will then have to pass a medical, which is not a foregone conclusion. Stoke City pulled out of a £5.5m deal for Ba two years ago as they were concerned about a long-standing knee problem.
But he has not missed a game for Newcastle because of that injury, although it is a condition which needs careful management and may yet be a stumbling block if there are insurance issues.
Ba's arrival will strengthen their strike force as Benitez still believes he can lead Chelsea to a title challenge. He secured what was arguably the most significant win of his reign on Merseyside. It was the most resilient since he took over as Frank Lampard underlined his enduring importance with both goals.
Chelsea have collected a maximum nine points over the festive period. "We have had some difficult games but especially this one because they haven't lost for a long time," said Benitez.
"It was a great win for us."