The 21-year-old scored within 60 seconds of his introduction, with starting debutant Ryan One, Jack Moylan and Rob Street also on target as the Imps stretched their unbeaten run to 15 matches, while the beleaguered Cobblers had former Lincoln loanee Jack Vale sent off early in the second half.

Freddie Draper sent a low shot straight at Ross Fitzsimons after seven minutes and four minutes later the Imps frontman played a lovely ball through to One, who beat the offside trap, took a couple of touches and nonchalantly drove home.

Moylan saw a terrific effort tipped over by the flying Fitzsimons, but the Irishman did double City’s lead six minutes after the break. He intercepted a poor Fitzsimons pass, broke into the area and passed the ball low into the far corner.

The visitors were reduced to 10 men after 56 minutes when Vale lunged two-footed at Ben House during a melee in the City box and was shown a straight red by referee Kirsty Dowle.

Fitzsimons produced a brilliant one-handed save to deny Street and again foiled him minutes later, before Varfolomeev fired home a stunning effort from 25 yards after 72 minutes.

Fellow sub Street crashed home City’s fourth from close range seven minutes later after Fitzsimons kept out Moylan’s effort.

Dom Jefferies hit a post at the death and seconds later had a shot saved by the busy Fitzsimons.