Mourinho says Ibrahimovic out for a month, as fellow striker Lukaku carried off

The Swede went off at half-time in United's Boxing Day clash with Burnley but Mourinho did not divulge the nature of his injury.

"Zlatan one month out," Mourinho told BT Sport when asked about United's striking options in light of the head injury sustained by Romelu Lukaku during Saturday's Old Trafford game against the Saints.

Lukaku was carried off on a stretcher wearing an oxygen mask early on after a clash of heads and United could not break down a stubborn Southampton side in his absence as they slipped to third in the Premier League.

The Belgium striker headed over a glorious chance before he was forced off and the hosts had two penalty appeals for handball turned down by referee Craig Pawson.

Mourinho was frustrated his side were denied a spot-kick.

"I think it is also a frustrating afternoon for Craig because he's a fantastic referee, one of the most promising referees in Europe. I feel bad for him," said Mourinho.

"We missed easy chances but there was a clear penalty that wasn't given.

"I'm happy with the players' attitude and the players' desires."

Southampton defender Maya Yoshida admitted he was fortunate not to concede a first-half penalty when the ball appeared to catch his arm.

He said: "Sometimes we get decisions from the referee and sometimes we get bad luck from them. Today we got good luck."

Yoshida was delighted with Southampton's response to their 5-2 defeat at Tottenham on Boxing Day.

"It was a really important point for us, especially after a really sobering couple of games," said Yoshida.

"We showed good spirit today."

Saints boss Mauricio Pellegrino made a big call by dropping goalkeeper Fraser Forster but his decision was vindicated as Alex McCarthy helped shut out United on his first Premier League appearance for the club.

"It's nice to come in again and play - I've been out a long time injured - but the main thing was we got a clean sheet and a point away from home," said McCarthy.