The St Leonards-based thrower lost by four sets to two against the unseeded Luke Humphries in the last 16 at Alexandra Palace, London, having led 2-0 at one stage.
Cross averaged 97.38, hit five 180s and was successful with 39% of his attempts at a double. Humphries averaged 99.71 with seven 180s and hit 40% of his shots at a double.
See also: * World Darts Championship: Rob Cross beats Cristo Reyes in straight sets* World Darts Championship: Rob Cross wins thriller against Jeffrey De Zwaan* Cross sinks Taylor to win world titleFew would have predicted the eventual outcome as Cross impressively clinched the first set 3-0 averaging 104.9.
The world number two then edged the second set 3-2 by hitting double one after Humphries missed five darts at a double to level the match.
Cross, who landed outshots of 116, 107 and 106 in those first two sets, took the opening leg of the third set, but Humphries came surging back to win the next three legs, sealing the set with a 115 checkout.
A 114 outshot put Humphries 2-0 up in the fourth set and although Cross ended a run of five successive losing legs in the next, Humphries finished 64 to bag the set 3-1 and level the match at two sets all.
Cross held throw in 14 darts at the start of the fifth set, but Humphries - playing well above his position of 90th on the Professional Darts Corporation order of merit - claimed the next three legs to lead for the first time in the match.
The 28-year-old Cross went 2-0 up in the sixth set only for Humphries to again reel off three straight legs - in 11, 14 and 14 darts - to seal the biggest win of his career and set up a quarter-final meeting with 10th seed Michael Smith.
Cross, nicknamed Voltage, had achieved impressive victories over Cristo Reyes and Jeffrey De Zwaan in the previous two rounds, but there will be no repeat of his magnificent triumph 12 months ago.