The Blues were defeated on the road as their opponents, MK Dons, secured their first three points of the campaign.
Callum Hendry broke the deadlock, before captain Alex Gilbey found the net in similar fashion following two fine deliveries from the right by Aaron Nemane.
Joe Tomlinson then found the third in the final moments, firing into the far corner beyond a helpless Harry Lewis.
United started strong with Dan Adu-Adjei finding himself in behind, but Ben Williams’ header into the path of the forward was collected by ‘keeper Tom McGill.
Connor Lemonheigh-Evans had the Dons’ first attempt on Carlisle’s goal, lashing over by some margin.
On 14 minutes, Aaron Hayden drifted forward with the ball, before firing a left-footed shot from the edge of the box straight at McGill.
Four minutes later, Callum Hendry opened the scoring. A perfectly timed pass in behind found Aaron Nemane, whose delivery picked out the forward and he made no mistake from close range.
Joe Tomlinson looked to double their lead soon after, but his shot was saved low by Harry Lewis.
Following the goal, MK Dons grew in confidence. Tom Carroll had a great chance to take aim at goal, but instead found Nemane out on the right, whose cross ultimately landed in the arms of United’s shot-stopper.
The hosts’ skipper Alex Gilbey grabbed their second after Nemane once again delivered into the area - the right-sided defender constantly caused issues for Ben Williams in the opening half-hour.
Harrison Neal looked to pull one back for the Blues two minutes before the break, but his low drive landed the wrong side of the post.
HALF-TIME: MK Dons 2-0 United
New signing Dominic Sadi was introduced at half-time, replacing Ben Barclay, and he was involved straight away finding Mellish, whose chance from outside the box flew over the Dons’ crossbar on 46 minutes.
On 52 minutes, Lemonheigh-Evans hammered over from outside the box, failing to add a third for the hosts.
Archie Davies found Adu-Adjei superbly five minutes later, running beyond the MK Dons backline, prior to firing wide.
Nemane continued to be a danger to United’s defence in the second period, but luckily for the visitors he didn’t make the most of the chance, and neither did Stephen Wearne moments later, dragging an effort wide of Lewis’ post.
On 77 minutes, Neal found Sadi at the far post, whose effort forced a great save from the hosts’ goalkeeper.
In the closing stages, Paul Simpson’s side proved to be no threat in the attacking third, whilst the hosts were exactly that, adding a third late on through Tomlinson.
FULL-TIME: MK Dons 3-0 United
Teams:
MK Dons - McGill, Sherring, Gilbey ©, Wearne (80’ Leigh), Tomlinson, Nemane (89’ Tripp), Offord (53’ Tucker), Hendry (80’ Harrison), Maguire, Evans (89’ Williams), Carroll
Unused subs - Harness, Lewington
Carlisle United - Lewis, Davies, Lavelle, Hayden, Wyke © (72’ Kelly (84’ Butterworth)), Adu-Adjei (67’ Armstrong), Vela, Neal, Williams (72’ Ellis), Mellish, Barclay (46’ Sadi)
Unused subs - Breeze, Allan
Goals:
MK Dons - (18' Hendry), (31' Gilbey), (90+2' Tomlinson)
Carlisle United - N/A
Match officials:
Referee - Farai Hallam
Assistant Referee - Ryan Whitaker
Assistant Referee - Damith Bandara
Fourth Official - Jonathon Block
Attendance:
6,399 (734 away)