Like their hosts, Pompey are also in fine form, and they will look to extend their unbeaten league run to 19 matches.
Match preview
After being beaten by Sheffield Wednesday in playoff final last season, Barnsley experienced a change in the managerial dugout over the summer after Michael Duff opted to try a fresh challenge with Swansea City.
Duff's successor Neil Collins got off to a flying start with a dominant 7-0 win over Port Vale, but one point from the next three league games left the new boss with work to do.
Since losing to Oxford United on August 19, the Tykes have enjoyed an upturn in fortunes, claiming four straight competitive wins all by a 2-0 scoreline.
In Saturday's home meeting with Burton Albion, a brace from Devante Cole proved enough to guide Barnsley to all three points, ensuring they finished the weekend in fifth position.
After beating Pompey 3-1 at Oakwell in March, the Tykes will be hopeful of replicating a similar scoreline in Tuesday's home encounter.
Portsmouth, meanwhile, are in a positive mood after they extended their unbeaten run to 18 league games in dramatic fashion.
Their impressive form looked set to come to an end on Saturday when Derby County's James Collins scored an 86th-minute penalty to put his side in front, but Colby Bishop proved to be Pompey's hero, producing a stoppage-time equaliser to rescue a point.
As a result, Portsmouth head into the midweek encounter in sixth position and level on 13 points with Barnsley after seven games.
While Mourinho will be pleased with Pompey's unbeaten run, he may be frustrated with the fact his side have drawn 11 of their previous 18 matches in League One.
Their habit of drawing games has been particularly prevalent on their travels, with six of their last seven league meetings finishing all square.
Barnsley League One form:
D
L
L
W
W
W
Barnsley form (all competitions):
L
L
W
W
W
W
Portsmouth League One form:
W
W
D
D
W
D
Portsmouth form (all competitions):
D
W
D
L
W
D
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Team News
Luca Connell remains sidelined for the hosts due to illness, while Robbie Cundy is also ruled out as he continues to recover from injury.
After claiming a 2-0 victory over Burton at the weekend, Barnsley boss Neill Collins could be tempted to name an unchanged lineup for the midweek contest.
Having netted eight goals in seven appearances this season, Cole is currently the league's top scorer, and he will be looking to score in a fifth consecutive league game on Tuesday.
As for the visitors, they are still expected to be without the services of Tom Lowery, Kusini Yengi, Anthony Scully and Christian Saydee.
Joe Morrell and Joe Rafferty are set to return from suspensions, although the pair are unlikely to feature in the starting lineup at Oakwell.
After coming off the bench to make his debut on Saturday, Chelsea loanee Tino Anjorin is in contention to start against Barnsley.
Barnsley possible starting lineup:
Roberts; Williams, Lopata, McCart; Cotter, Phillips, Russell, Kane, Cadden; Cole, McAtee
Portsmouth possible starting lineup:
Norris; Swanson, Poole, Shaughnessy, Ogilvie; Robertson, Pack; Whyte, Anjorin, Lane; Bishop
We say: Barnsley 1-1 Portsmouth
Pompey have not lost an away league game since losing to the Tykes in March, and we think they will extend their unbeaten run on Tuesday.