The Dons have won two of their three friendlies so far, while Pompey boast a perfect pre-season record with three victories from three.
Match preview
MK Dons are gearing up for a third consecutive season in League Two after a humiliating 8-1 aggregate defeat to Crawley Town in the play-off semi-finals, their heaviest play-off loss in the EFL's history.
This was the sixth time the Dons have reached the play-offs without progressing to the final, a record manager Mike Williamson will be keen to rectify.
The Buckinghamshire side will be aiming to replicate their 2007-08 League Two title-winning campaign or their 2018-19 automatic promotion to League One.
Their pre-season form has been inconsistent, with a 2-1 loss to Barnet followed by wins over Chelmsford (1-0) and Wealdstone (3-1).
With friendlies against Portsmouth and Plymouth Argyle still to come before their League Two opener against Bradford City on 10 August, Williamson will be hoping to see increased intensity from his side.
Portsmouth, however, will provide a stern test, as John Mousinho's men are unbeaten in pre-season, scoring eight goals and conceding just once.
The Hampshire outfit are back in the Championship for the first time since 2011-12 after winning the 2023-24 EFL League One title.
This is a significant opportunity for Pompey following seven challenging years in League One, including back-to-back play-off semi-final defeats and three seasons outside the play-off places.
The Championship will present a new challenge for Mousinho's side, and they will be eager to make the most of their remaining pre-season fixtures before their opening game at Leeds.
MK Dons friendly form:
W
W
MK Dons form (all competitions):
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D
L
L
W
W
Portsmouth friendly form:
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W
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Portsmouth form (all competitions):
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L
W
W
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W
Team News
Williamson named a strong starting XI for MK Dons' win over Wealdstone, with Callum Hendry, Liam Kelly, Luke Offord and Joe Pritchard getting their first starts on British soil.
Tom McGill also made his debut for the Dons, while Stephen Wearne, Joe Tomlinson and Matt Dennis were on the scoresheet.
Mousinho has been making good use of his entire squad during the pre-season friendlies and that is likely to be the case again when Portsmouth take to the pitch on Tuesday.
New signing Jordan Williams was on the scoresheet against Bognor Regis Town, and he will be looking to start in defence against MK Dons.
MK Dons possible starting lineup:
Norris; Williams, Shaughnessy, Towler, Ogilvie; Pack, Stevenson; Scully, Lang, Murphy; Yengi
Portsmouth possible starting lineup:
McGill; Sherring, Offord, Maguire, Pritchard; Tomlinson, Kelly, Williams, Gilbey, Wearne; Hendry