Snodgrass made more substantial contact when Wes Hoolahan whipped in a fine left-wing cross, but the ex-Leeds midfielder's header drifted comfortably wide of Lindegaard's far post. Within long, Javier Garrido fizzed a dangerous, low cross through a similar course, only to see it evade target man Grant Holt.
The hosts were increasingly menacing in attack - though they did waste a presentable opening when Smalling's scuffed clearance culminated only a blocked shot from Bradley Johnson - and it took a superb sliding clearance from Smalling to stop Holt from turning in Snodgrass' cross.
Shortly before the break came United's clearest chance of the half, only for van Persie to get himself in a tangle in trying to reach Giggs' beautifully-flighted ball through the middle.
That opening sparked a late spell of pressure from United, and Ruddy produced a superb reaction save to fend away Young's half-volley through a crowded penalty area. Nevertheless, the interval arrived with the points still in touching distance of both sides.
As in the first period, United began the second half brightly. Young's well-weighted pass released van Persie and, though he took two attempts to bring the ball under control, the Dutchman brought a solid save from Ruddy with a low, near-post effort.
Norwich hit straight back and pressured Lindegaard with a deep free-kick from Snodgrass, but in open play both sides continued to serve up a dearth of excitement until just before the hour mark, when Garrido's superb cross was expertedly guided past Lindegaard by Pilkington.
The goal prompted Sir Alex Ferguson to introduce Paul Scholes and Danny Welbeck in place of Chicharito and Valencia, and Welbeck came close to