Southend 0 Portsmouth 2: Neil Allen's match report
The striker serving his Pompey debut as a right-back laid the foundations for progress into the quarter-finals of the Checkatrade Trophy.
Dan Smith, the home-grown product with 12 goals on loan at Bognor this season, was pressed into an unfamiliar defensive role at Southend.
A mere 93 seconds into his Blues bow, the 19-year-old took a touch before flighting a right-footed cross into the hosts' penalty area.
Louis Dennis leapt the highest, steering a header into the top corner of the net from around eight-yards out to put Kenny Jackett's men on the road to victory '“Â and ensure Smith made an instant impact.
Evans then sealed the 2-0 victory on the stroke of half time in front of the 1,649 crowd, containing 189 travelling fans.
It booked a quarter-final spot for the Blues, moving out of the regional section for Thursday evening's scheduled draw.
And, irrespective of the lack of affection for the Checkatrade Trophy, this excellent Pompey squad remain involved in three separate competitions.
Jackett had made 10 changes to the side which won 1-0 in the FA Cup at Norwich in such memorable circumstances.
Evans was the sole survivor from the starting XI, although goal-hero Andre Green was promoted from the bench for the Roots Hall fixture.
Danny Rose was meant to be included yet, with a move elsewhere close, his Pompey swansong did not materialise.
Having been handed the perfect start through Dennis, Jackett's men should have extended their lead on 27 minutes, only for Wheeler to roll the ball past the far post with just the keeper to beat.
It was 2-0, though, during one minute of time added on, Dennis cutting in from the right and nudging the ball to Evans, who crashed home a right-footed first-time shot.
Pompey brought on Freddie Read for Andre Green at the break, while the Academy's Leon Maloney was handed his debut on 54 minutes, replacing Bradley Lethbridge.
The match petered out with Southend enjoying more pressure, albeit without troubling Alex Bass, and Pompey maintained their Checkatrade Trophy march.
Pompey: Bass, Smith, Burgess, Casey, Haunstrup, Evans, May, Wheeler, Dennis, Green (46mins Read), Lethbridge (54mins Maloney).
Subs not used: Durin, Clarke, Lowe, Hancott, Mnoga.
Southend: Smith, Bwomono, Moore (59mins Hutchinson), White, Hendrie, Kightly (46mins Dieng), Hyam, Yearwood, Bunn, Robinson, Cox (46mins McLaughlin).
Subs not used; Bishop, Turner, Mantom, Klass.
Attendance; 1,649 (189 away)