Fine goals by Henrikh Mkhitaryan and Zlatan Ibrahimovic gave Manchester United a 2-0 away win over Zorya Luhansk and booked their place in the Europa League knockout stages as group runners-up.
United, for whom a draw would have been enough, began brightly on a freezing night in Ukraine, stringing together some neat passing moves despite a hard and bobbly pitch.
But the home side posed the first serious threat, with only United goalkeeper Sergio Romero standing between them and a shock lead before 10 minutes had been played.
Midfielder Ihor Kharatin fired in a bending shot from 20 yards which Romero tipped away before Ivan Petriak put the rebound into the side netting from an angle.
With 12 minutes gone, United's Ander Herrera saw a low effort easily saved by home goalkeeper Igor Levchenko.
But Levchenko was scrambling when Ashley Young and Ibrahimovic worked the ball to Pogba outside the area and the France international's fierce shot flew just past the post.
United tried to pick up the pace after 23 minutes as Pogba threaded a pass through to Rooney on the left-hand side of the area, but he overran the ball and the chance was gone.
Ten minutes from the break United were caught in possession and Zorya came forward, with Olexandr Karavaev whistling a well-struck half volley wide of the post after the ball had fallen to him on the edge of the box.
Eric Bailly tried his luck with an acrobatic bicycle kick after a corner at the other end, but the match was becoming increasingly scrappy and United, despite their dominance of possession, were struggling to create chances.
As the first half came to a close, Ibrahimovic laid the ball off to Rooney, whose low 25-yard effort was held by Levchenko at his near post.
The keeper got his fingertips to a deflected Rooney strike as United threatened again before Rojo fired over with the final kick of a drab opening period.
But within two minutes of the restart, United had the lead in style.
Marcos Rojo won the ball back in midfield and Mkhitaryan ran at the heart of the Zorya defence, weaving his way into the penalty area before firing home the coolest of low finishes for his first United goal.
Moments later, the former Borussia Dortmund man again made space for himself, but this time his final pass was too far ahead of Ibrahimovic.
The United No. 9 then latched on to a Pogba knockdown but fired his effort too close to Levchenko.
Zorya made two changes in quick succession, bringing on Emmanuel Bonaventure for Denys Bezborodko and replacing Kharatin with Dmytro Grechyshkin.
Bonaventure added a more direct edge for the home side, forcing Bailly into a good challenge as he tried to burst into the area.
Bailly needed treatment after the same player challenged him for a header and he landed heavily, but the defender was able to continue.
Mourinho replaced Rooney with Marouane Fellaini, having earlier replaced Mata with Jesse Lingard.
With 73 minutes gone Romero made his second important save of the night, blocking Sivakov's header after United's defence had switched off at a free kick.
As the visitors began to run down the clock, goal-scorer Mkhitaryan made way for Timothy Fosu-Mensah in their final change.
And their victory was confirmed when a fine pass from Pogba put Ibrahimovic through and he slid the ball home to remove any lingering doubts about the result three minutes from time.