A Zlatan Ibrahimovic hat-trick gave Manchester United a comfortable three goal lead in their Europa League Round of 32 tie against St Etienne on Thursday night.

The home side opened the scoring after a quarter of an hour when the 35-year-old's deflected free-kick wrong-footed Stephane Ruffier in the French side's net.

That goal settled the nerves after what had been a shaky start at the back for United, with Eric Bailly making two botched clearances that nearly let the visitors in on goal.

Jose Mourinho's then kicked on in the second-half and Paul Pogba - who imposed himself more as the game wore on - went close shortly after the break with a magnificent effort on his left foot.

United eventually doubled their lead after a piercing run from substitute Marcus Rashford down the left ended in a cross that found Ibrahimovic unmarked at the back post for a tap in.

The big Swede then finished the game off from the penalty spot with two minutes left on the clock after being brought down in the box.

Here are five things we learned on the night...

1. Paul Pogba is thriving in a deeper role

Pogba found time and space against St Etienne (Getty Images)

Paul Pogba played in the slightly deeper role that he's occupied in United's last three or four games and looked a threat again.

With more space and time on the ball, the Frenchman was able to thread dangerous looking passes through for willing runners in the shape of Anthony Martial and Juan Mata.

With Michael Carrick well into the twilight years of his career, Pogba could be a very dangerous weapon for United at the base of their midfield.

It remains to be seen if he can be quite as effective there against the biggest sides, however, where his defensive discipline will come under more scrutiny.

2. Martial is proving himself after a tough start

Martial was a constant threat down the left (Getty Images)

Anthony Martial is starting to look more and more like the player United paid £40m for.

After a tough start under Jose Mourinho, the 21-year-old has impressed in recent games and continued his good form tonight.

One of United's best players against St Etienne, he was a constant threat down the left. The future looks bright for the Frenchman if he can carry on like this.

3. United would be lost without Ibrahimovic this season

The Swede opened the scoring with a deflected free-kick (Man Utd via Getty Images)

Zlatan Ibrahimovic got his 21st, 22nd and 23rd goals for United this season. While Martial and Juan Mata have been chipping in with a few of late, United look short of back-up for the big Swede.

Marcus Rashford, while he hasn't been given lots of chances this season, hasn't kicked on quite as well as hoped after his bright start last year and Wayne Rooney's time at Old Trafford looks to be drawing to a close.

United will have to strengthen in the summer and just pray their 35-year-old hitman doesn't get injured in the meantime.

4. Jose Mourinho probably doesn't know his best defensive partnership

Eric Bailly made two mistakes early on for United (Getty Images)

Phil Jones and Marcos Rojo have been regulars for large parts of this season, while Chris Smalling was one of United's best players last year and Eric Bailly was a big money signing in the summer.

The latter two were the partnership tonight but looked shaky.

Bailly, in particular, was out of sorts, making two botched clearances early on that can't have inspired confidence in his teammates.

When it really comes down to it and Mourinho is asked to pick his strongest pairing, who does he go for?

5. You can't put a price on a winning habit

Mourinho has instilled a winning mentality at United (Man Utd via Getty Images)

The hosts hardly played out of their skins this evening, but like so many times this season they managed to grind out a win.

After several years of limp defeats and a lack of direction, United have rediscovered the winning habit that was so characteristic of the Ferguson years.