JOSE MOURINHO believes Paul Pogba requires more time to readjust to English football after the France international scored twice in Manchester United's 4-1 Europa League win over Fenerbahce.

The world's most expensive player, who returned to Old Trafford from Juventus in the summer, opened the scoring with a penalty before claiming his second with a long-range strike after Anthony Martial had doubled the lead with another spot-kick.

Jesse Lingard added the fourth early in the second half, prior to a consolation from former United forward Robin van Persie.

Speaking about Pogba, Mourinho told BT Sport: "Two days ago, he was the worst player of the Premier League and 48 hours later he's phenomenal.

"He needs time. I was in Italy, I know Italian football, I know the characteristics, I know the pace, I know the intensity and to be in Italy for four or five years and then come back to the Premier League I was not expecting (him to adjust) in a click of fingers.

"He needs time, even the top players sometimes they need time but I'm happy with the performance today because he gave us what we need."

Mourinho also insisted Pogba was his side's designated penalty taker, with captain Wayne Rooney having taken them in the past.

"The first penalty taker was Paul, we made that decision and then probably he didn't want to repeat because it's a second penalty a couple of minutes later," Mourinho added.

"And then probably because Martial was the one that had the previous action and Martial also is a good penalty taker, they made that decision, it's not a problem for me.

"I always give the indication of the one who has the responsibility to take but with the freedom for the other guys to make a decision on the pitch."

The win puts United level on six points with Feyenoord at the top of Group A after Mourinho's men were beaten by the Dutch side in the opening round of matches.

"After a defeat in the first match, it is very important for us to make nine points at home and try (for) a few more in the matches away so a very important victory for us," Mourinho continued.

"I think they came with a good defensive plan and they stopped us for the first period of the game but then they we had the first two goals, two clear penalties which opened the door for quality.

"I think we played well for periods but then with the fourth goal I think we stopped which is natural and they tried to have a reaction, which they did.

"I'm never happy to concede a goal, especially if the goal is not a perfect one. The important thing is we have six points and two victories at home."

Earlier, Southampton manager Claude Puel dismissed suggestions his rotation system was responsible for their "unlucky" 1-0 Europa League defeat at Inter Milan.

Antonio Candreva's exceptional second-half goal secured an important victory for Inter at the San Siro that prevented their visitors from building a lead at the top of Group K.

One of the most glamorous fixtures in Southampton's history concluded with them third in the group when they could have taken a significant step towards reaching the knockout stages.

Despite being reduced to 10 men after Marcelo Brozovic's red card, Inter have returned to contention after winning their first points.

Defeat also came after Puel made six changes from the starting XI he had selected in Sunday's 3-1 defeat of Burnley - an injury suffered by Matt Targett meant one was forced upon him - which included goalscorers Charlie Austin and Nathan Redmond.

Asked if his changes had disrupted his team, Puel responded: "No. I think if you can play a very good game... We have all the time fresh players to play good football. This is very, very important.

"Not all the players can play good football (if they play every game). It's important to consider all the players. We want to go for the qualification with all the squad and not just 11 players.

"We can see (we played a) good game with the quality against Inter away it is difficult to think and to answer the question. It's a very, very good game and unlucky. We are just unlucky.

"We do good work and with all the many chances we can play very good on the ground with quality, and just (need) a goal to be rewarded for all this good play. It is a frustration."

Southampton had fine chances to score in the ninth minute, when Jay Rodriguez conceded possession after hesitating from a shooting position, and in the second half through Virgil van Dijk.

The central defender similarly missed a fine chance in the recent 0-0 draw away to Israel's Hapoel Be'er Sheva, and on this occasion produced too casual a finish saved by Samir Handanovic when requiring only a routine finish from directly in front of goal.

Puel also recognised the return against Inter in a fortnight has become "interesting", while Van Dijk told BT Sport: "We were the only team that deserved to win and to concede a goal with their only chance frustrated.

"We should have had the game dead and buried in the first half but that is what happens if you don't take your chances.

"I had a big chance with my left foot and a header. We had so many opportunities to win the game."

The result also relieved some of the pressure that had been building on Inter manager Frank de Boer, and the Dutchman said: "They created some very dangerous chances. We knew that they were very dangerous.

"At first there were small chances for both of us. Luckily we have a great goalkeeper, he was unbelievable. The result for the group? It's very important for us."

Elsewhere, Dundalk tasted bitter disappointment as they went from the verge of an historic victory to defeat against Zenit St Petersburg.

A touch of Brazilian class saw scheming Zenit midfielder Giuliano exchange a one-two in the box with Belgian Axel Witsel and ease it into the net from close range for a 2-1 victory in their Group D Europa League clash in Dublin.

Substitute Mauricio missed a penalty chance to finish the game off in the final minutes.

Prior to that, Robert Mak had put the Russians level after Patrick McEleney's opener for Dundalk.