Kinnear was taken to hospital on the morning of the game as a precaution after complaining of feeling unwell.
Without him at the helm, his side won for the first time in seven games - and only the second time away from home this season - in an error strewn game that was decided by a series of defensive howlers before half-time.
Three of the goals came in a frantic opening nine minute spell with Damien Duff giving Newcastle the lead after just 65 seconds, Marc-Antoine Fortune equalising and then Peter Lovenkrands scoring his first goal for Newcastle.
Albion had won three of their last four home games, but all hopes of a dramatic comeback in this match effectively evaporated four minutes before half-time when Steven Taylor struck.
A second from Fortune in the 73rd minute briefly raised Albion hopes of a comeback, but Borja Valero wasted their best chance to complete the most dramatic of comebacks when he headed a Paul Robinson cross narrowly wide.
The victory kept Newcastle clear of the drop zone and in the context of the season it could be a crucial result.
Albion had been chasing a victory to leapfrog over Newcastle but they remain rooted to the bottom of the table after a defensive display that left manager Tony Mowbray fuming.
Leon Barnett, not for the first time this season, found himself culpable when he handed Duff Newcastle's opener.
The gangly central defender got himself in a terrible muddle trying to clear a pass from Shola Ameobi.
All he managed to do was push the ball into the path of Duff, who gave Scott Carson no chance from eight yards.
Having gifted Newcastle the advantage, it was somewhat ironic that a mistake in the United backline handed Albion a rapid route back on to level terms.
Valero pounced on a fourth minute clearance from Nicky Butt and picked out Fortune.
The on-loan Nancy marksman was being marshalled by Taylor but he slipped at just the wrong time and Fortune spun away before drilling a low, angled drive across Steve Harper.
Both sides would have hoped that would have been the end of any comical defending.
But things went bad from to worse for Albion when Lovenkrands ended a frantic opening nine minutes by regaining the lead for Newcastle.
Duff's left-wing cross picked out Taylor and his shot was cleared by Barnett only to bounce off the other Albion centre-half Abdoulaye Meite.
Unfortunately for Albion, the ball then flew invitingly to the foot of Lovenkrands, who made no mistake with a clinical finish from 14 yards.
If Meite thought his day couldn't get any worse it did four minutes before half-time when Taylor made amends for his earlier slip to increase Newcastle's advantage.
Taylor got away from the attention of Meite to stoop and head home a Ryan Taylor corner as Albion's defence was carved open again.
That should have been enough for Newcastle to cruise to victory but Albion ensured it was a nervy finale when Fortune grabbed his second.
The goal infuriated Newcastle as play momentarily stopped with Albion striker Roman Bednar down and appearing to need treatment.
Albion midfielder Robert Koren looked set to play the ball into touch but, when Bednar got to his feet, Koren played the ball forward.
It eventually found its way to Filipe Teixeira and his neat pass picked out Fortune, who again beat Harper with a low angled drive but it was ultimately too little to late.