Six months on from the night Ruiz stunned boxing, Joshua risked seeing his career left in tatters with a second defeat, but served up 36 minutes of movement and well-timed punching to take the IBF, WBA and WBO titles back to Britain.
After cutting his Mexican rival inside the first round he never looked back and picked out smart jabs and right hands throughout before being serenaded with chants of “AJ, AJ, AJ” by 14,000 or so fans in the Diriyah Arena.
Ruiz never looked close to landing a knockdown and when scores of 118-110 118-110 and 119-109 were read out, Joshua jumped up and down in the ring in celebration, just as the man who had wrecked his US debut did in June.
Joshua, 30, now joins a small cluster of men including Muhammad Ali, Lennox Lewis, Evander Holyfield, Mike Tyson and Floyd Patterson to have reclaimed the world heavyweight title.
Patterson fell to the canvas seven times in one round as he lost his belts to Ingemar Johansson in 1959 but regained them in a rematch. The question in Saudi Arabia was whether Joshua could show the same mental fortitude after being knocked down multiple times by Ruiz in June. His answer was emphatic.
A downpour in a country that barely sees rain stopped moments before Joshua strode to the ring, prompting him to carefully dry his feet on the canvas.
From that moment on, his feet moved with grace. Seconds before the off, Ruiz was told “let’s go Andy” by his corner but he was rarely allowed to get close to his rival and inflict the damage he did in the first fight.