It was Stockport who had the best chance of the first half as David Poole found himself in space behind the Saints defence but was denied by Kelvin Davis saving at his near post.
An anxious St Mary's crowd were expecting a goal feast, but had to wait until the 63rd minute for Lambert to satisfy their demand.
Stockport goalkeeper Owain Fon Williams attempted to punch away Joseph Mills' outswinging corner, but inadvertently directed it towards Lambert who knew little of the goal as it struck his back and floated over the line.
Waigo then missed two golden opportunities, first with a header from a Lee Holmes cross that he placed wide and then a driven strike straight at Fon Williams when sent clear by Morgan Schneiderlin's pass. The Senegalese frontman made amends after 69 minutes as he cushioned Jon Otsemobor's cross and stabbed his finish past Fon Williams from two yards out.
Source: Team Talk
Source: Team Talk