Odion Ighalo insists he does not care about those who doubted his Manchester United credentials after his two goals helped secure an FA Cup quarter-final spot.

The striker was signed on loan until the end of the season on deadline day in January from Chinese Super League side Shanghai Shenhua.

There was criticism of United's apparent last-minute scrambling to sign a forward as back-up for Anthony Martial and the injured Marcus Rashford, particularly with Romelu Lukaku and Alexis Sanchez having been allowed to join Inter in the previous window.

Ighalo has responded to the doubts in style, though, having scored three goals in just two starts for the Red Devils.

After netting on his Old Trafford debut for United in the 5-0 Europa League thrashing of Club Brugge last week, Ighalo scored twice against Derby County on Thursday to secure a 3-0 victory for Ole Gunnar Solskjaer's side.

The 30-year-old is already a popular figure among the fans and insists he is only concerned by the thoughts of supporters, his manager and his United team-mates.

"I'm happy for the goals, first of all," Ighalo told BT Sport.

"As long as my team-mates believe in me, the boss believes in me, the fans believe in me, I just have to keep going. I don't care what people say outside."

United went ahead through Luke Shaw's fortuitous volley, which bounced off the turf and seemed to clip team-mate Jesse Lingard before looping over goalkeeper Kelle Roos.

The full-back had only scored once before for the club and he is not prepared to allow Lingard to take this goal away from him.

"I'm claiming it! No chance – he can't claim that!" Shaw said. "I think there was too much spin because I didn't hit it correctly, but he can't claim that.

"I'm very happy. Most important was the win and another clean sheet for the boys. Hopefully, there are more goals from me to come."

United have now gone nine matches without defeat across all competitions and kept clean sheets in seven of those, and Shaw says they go into Sunday's derby with Manchester City in a positive mood.

"We're in a very confident period at the moment with results and keeping shut at the back," he said. "We're very confident. It's a massive game Sunday and we're looking forward to that."