Right-back Janmaat, who impressed with the Netherlands during their run to the World Cup semi-finals, made his first appearance for his new club at the John Smith's Stadium on Tuesday, having joined from Eredivisie side Feyenoord last month.
Yet it was Cabella who stole the show with a superb lofted finish two minutes from time, after Huddersfield debutant Radoslaw Majewski and Jon Stead had turned things around following Emmanuel Riviere's opener.
Both sides created early chances, Oliver Norwood flashing a free-kick wide for Huddersfield before Yoan Gouffran scuffed an effort wide at the other end.
Gouffran soon atoned for his miss as he set up the opener in the 16th minute, his deflected cross leaving former Monaco man Riviere with the simple task of tapping in from point-blank range.
Opportunities proved less frequent thereafter, but Majewski levelled in spectacular fashion in the 36th minute.
The former Nottingham Forest man curled a superb strike into the top corner, past a helpless Tim Krul in the Newcastle goal.
Huddersfield changed their starting XI after the interval and began the second half the brighter, midfielder Duane Holmes testing Krul with a fierce drive from the edge of the area.
The hosts' attacking initiative paid off in the 66th minute when Stead's low strike deflected beyond Krul to give Huddersfield a lead they arguably deserved.
Paul Dummett powered narrowly wide from distance as Newcastle pushed for a leveller.
Their efforts were ultimately rewarded when Cabella, who also scored against Schalke on Sunday, latched on to a quick free-kick from substitute Ayoze Perez before lofting a wonderful chip over Joe Murphy and into the net to ensure the game ended all-square.