The natives jeered in disapproval of the boy from Barnsley who pooped their promised party. The Valencians had gathered to witness a clean sweep by the Spanish armada in the men's 3,000m final. Instead, they saw Mayock sweep to the most dramatic of the three victories secured by Britain's athletes here in Spain's third city.
Like Ashia Hansen, winner of the women's triple jump with a new world indoor record on Saturday, and Jonathan Edwards, who took the men's triple jump title last night, Mayock made it to the top of the medal podium. He did so, however, with the sound of Spaniards booing his ascent to the top step and jeering every note of the National Anthem. "I know how the bulls must feel over here," he later reflected.
It was a sour note on which to end the three days of competition. And it was entirely unfair on Mayock, who was guilty of committing nothing more criminal than fight his ground and snatch the golden opportunity that beckoned him on the final lap of a bruising but entirely fair battle.
It was the defining moment of a race run with tactical astuteness by the 27-year-old protege of Britain's recently appointed middle distance running coach, Peter Elliott. Intelligently positioned from the start, Mayock made his move before the final bend, in the process rudely halting the charges of the two Spaniards poised to strike behind him.
Manuel Pancorbo and Alberto Garcia had to settle for silver and bronze respectively - and Isaac Viciosa, the third Spaniard in the final, for medal-less fourth place - as Mayock strode clear in the home straight, stopping the clock at 7min 55.09sec.
Despite the cacophony of catcalls, Mayock's decisive move and the elbowing for position that persisted from the gun was all part of the rough and tumble of racing on a banked indoor 200m track. The official protest lodged before Mayock received his medal from the Mayor of Valencia - a Spanish inquisition - was never likely to be upheld.
Pancorba complained: "If he'd had chisels on his elbows I would have had holes in my chest." Mayock retorted: "The Spaniards were shoving me all over the place in the heats and with three laps to go Pancorba gave me a nasty push. Racing indoors is a physical business."
It could have been worse for Mayock. "Peter Elliott told me he'd break my legs if I didn't win," he related. Instead, he made the breakthrough he has been threatening since winning the World Student Games 5,000m title seven years ago, showing the same streak of South Yorkshire steel that prompted the tabloids to christen his mentor, "The Tough of the Track.''
Elliott, the Commonwealth 1500m champion in 1990, was a proud bystander last night, a satisfactory one for Britain but a truly great one for the north of England. The other three British medal winners on the final day are members, respectively, of Gateshead, Sale, and Liverpool Harriers.
Edwards struck his gold, for Britain and for Gateshead, with a first round jump of 17.43m. But his medal success was a mere formality compared to those of Allyn Condon, who sprinted to bronze in the men's 200m final, and Diane Allahgreen, who was third in the women's 60m hurdles.
Condon's run eased the disappointment of Julian Golding, who arrived here as favourite, finishing outside the medals in fourth. And Tony Jarrett's failure to survive the semi-finals of the 60m hurdles was another unexpected low for the British team.
Janine Whitlock, however, hit the heights in a women's pole vault final won by Ukrainian Anzhela Balakhanova with a new world indoor record, 4.45m. Whitlock could not match the medal-winning prowess of Condon and Allahgreen, fellow residents on Merseyside, but improving her British record to 4.25m was commendable compensation for fourth place.