The goal stopped Leeds United pulling level on points with Slaven Bilic's men thanks to a victory by the same scoreline over Birmingham City.
Preston North End suffered late heartache as Mark Bowen began his tenure as Reading manager with a 1-0 win, while Barnsley held Swansea City but slipped to the bottom of the table.
As a result, high-scoring victories for Queens Park Rangers and Charlton Athletic served to bunch up the chasing pack.
On a productive weekend for teams at the other end of the table, Stoke City claimed back-to-back league victories for the first time since October last year by beating Fulham 2-0.
KANU BELIEVE IT?
Fresh from signing a contract extension, Wales striker Robson-Kanu was the man to benefit from an 82nd-minute goalmouth scramble at Riverside Stadium.
It meant back-to-back wins for the Baggies since slipping up against Leeds at the start of the month, with the Elland Road outfit forced to be patient in its pursuit of three points against Birmingham this time out.
In the week the club celebrated its centenary, Leeds-born Kalvin Phillips made himself an appropriate match-winner with an emphatic 65th-minute finish.
The same scoreline belatedly arrived at Madejski Stadium, when defender Matt Miazga turned home in the eighth minute of stoppage-time after Preston goalkeeper Declan Rudd saved from Jordan Obita.
Reading moved up to 19th, two points clear of the drop zone, with Preston dropping to sixth — Swansea climbed to third despite managerless Barnsley finding a swift response to Andre Ayew's 67th-minute opener through Alex Mowatt.
EZE HOLDS NERVE AMID LATE DRAMA
QPR was heading for a 1-1 draw at KCOM Stadium until Ebere Eze won and converted a pair of late penalties.
Hull City, which led through Jarrod Bowen, set up a grandstand finish when Northern Ireland international Josh Magennis scored his first league goal for the club deep into stoppage-time, but it finished 3-2.
Philipp Cocu's troubled Derby County tenure continued with a 3-0 loss at The Valley.
Macauley Bonne and Naby Sarr on target for Charlton before Conor Gallagher capped the triumph with a fabulous long-range effort.
IT'S THE SOUND OF THE TYRESE
Former Manchester City youngster Tyrese Campbell put Stoke on the way to a 2-0 win over Fulham that lifted it off the bottom of the table.
Scott Hogan was brought down by Cottagers goalkeeper Marcus Bettinelli 10 minutes from time and Lee Gregory, who set up the opener with a flick-on, made light of the Potters' dismal recent record from the spot by converting.
Ollie Watkins missed a first-half penalty but was Brentford's stoppage-time hero as he sealed a 3-2 win over Millwall, which led 2-0 heading into a remarkable final six minutes at Griffin Park.
Luton Town was a 3-0 winner against Bristol City, while Blackburn Rovers and Huddersfield Town shared a 2-2 draw in the early kick-off.