Stevenage were made to work hard for the victory which secured their place in the end of season play-offs as Carlisle defended resolutely and almost struck back on the break as they looked to continue their own impressive recent run of form.
Stevenage started on the front foot and a cheeky run from Martin took him to the byline. His deep cross had the defence stretched but Beardsley couldn't quite rise high enough to apply the finishing touch.
More good work on the right flank took Pett past Grainger and he delivered early as home shirts flooded the box. Young dropped deep to head behind but Carlisle had to concentrate as two corners followed. Bond was unmarked at the back stick for the second of the deliveries and his volley from 12 yards had to be diverted past the upright by Young, who had taken up a good position at the back post.
It was all about the home side through the early phase of the game and a fizzed cross from the lively Pett went just behind Beardsley as he bent his run. More danger followed when Whelpdale pounced on a loose pass in midfield. He carried it forward and Gillespie had to readjust to make the save as it touched Grainger and angled at his legs.
Stevenage kept the pressure on and they should have notched when Whelpdale and Bond combined to make space for another telling delivery. Beardsley was on his own, dead central, but he took his eye off it and miscued a poor volley back towards the corner flag.
Whelpdale took matters into his own hands on the half hour when he cut in to run across the face of goal. He ignored the runners left and right and crunched a firm shot into the side netting.
Boro came again moments later when Conlon spun away from Brough and into the channel. He sized up his options and was a whisker away as his dipping effort curled just past the woodwork.
Slick passing between Whelpdale and Parrett left Beardsley with a difficult chance as he took possession with his back to goal. An instinctive shot was heading for the bottom corner until Grainger slid back to make a vital block.
The dangerous Whelpdale came again on the stroke of half time when he dropped a shoulder 30-yards out. He went for precision and it almost paid off until Gillespie stuck out a hand and tipped it wide.
United survived a late scare in time added on for the half when Whelpdale connected with a volley from a near post corner. It had plenty of power but he could only find the side of the target.
The stubborn resistance of the first half was made to count for nothing just two minutes after the break when Whelpdale ran free on the right. His cut back found Parrett in acres of space and his deflected shot dipped over Gillespie's dive and into the bottom corner.
Boro followed up their breakthrough with blocked shots from Beardsley and Wells, but it was United who should have registered when Dempsey burst free on the left wing. His low cross ran through to the back post but it bobbled nastily and Potts shanked a poor shot into the stands from very close range.
Carlisle survived another scare when an Andrade shot spun wide off O'Hanlon but they were left to rue another miss of their own when Kennedy twisted and turned before clipping the ball high. Beck got there before Day but he couldn't keep his header down.
Tom Pett thought he'd secured the win when he unleashed a thundering effort following another good run down the right. The cheers of the crowd were cut short as his stinger pinged back off the angle of post and bar.
A late Carlisle corner caused problems as Day slipped when he tried to punch it, but Boro survived to hook it clear despite the best efforts of O'Hanlon and Rigg as they tried to get a touch.
More good work from Rigg brought another corner in time added on, and Dempsey had hearts in mouths when his shot just missed, but the hosts kept their concentration and extended their unbeaten run to seven games to take them into the play off games in confident mood.
Stevenage - Parrett (47)
United - Kennedy (36), Dempsey (79)
Stevenage - Day, Dembele, Bond, Whelpdale, Pett, Parrett (Jebb 90), Wells, Beardsley, Okimo, Conlon (Andrade 57), Martin (Kennedy 66). Subs - Beasant, Walton, Henry, Deacon.
Carlisle United - Gillespie, Young (Dicker 77), Atkinson, O'Hanlon, Grainger, Brough, Potts, Griffith (Rigg 54), Kennedy, Dempsey, Wyke (Beck 5). Subs - Hanford, Buddle, Paynter, Thirlwell.
Referee - Mr Darren Drysdale
Attendance - 3,632 (478 away fans)