Ander Herrera believes Manchester United are hitting top form just at the right time, ahead of next Sunday's (10 December) derby.

The 20-time champions of England will go into the first derby of the season trailing Manchester City by eight points but confidence at Old Trafford appears to be building nicely, on the back of consecutive away wins against Watford and Arsenal.

Saturday's 3-1 win at the Emirates was their first away win against top-six opposition under Jose Mourinho in eight attempts and Herrera believes United have what it takes to inflict City's first defeat of the season.

"We are going to find our best moment very soon," Herrera told United's official website.

"We are second and chasing to be top of the table.

"It was a fantastic result [at Arsenal] with some great performances. David [de Gea] was amazing, and we were clinical in the first half, with two chances in the first 15 minutes and two goals."

Antonio Valencia opened the scoring against Arsenal, before Jesse Lingard scored twice either side of Alexandre Lacazette's strike to give United their fourth consecutive Premier League win. The England international had gone without a league goal until Tuesday (28 November) but now has three in two games and was instrumental against Arsenal, as was Paul Pogba, who set up two goals.

The Frenchman, however, will unavailable against City after receiving a straight red card for stamping on Hector Bellerin's leg, but Herrera insisted United have reasons to be optimistic even without their record signing.

"Jesse [Lingard] is on fire now, Paul [Pogba] as well, it's a pity he got a red card," he added.

"Romelu [Lukaku] didn't score but he helped us a lot. The centre-backs - Victor [Lindelof] is in fantastic form right now. So we are optimistic of course."

City won at Old Trafford last season as Mourinho and Guardiola first met in the Premier League in what remains the last defeat United have suffered on home turf under the Portuguese coach. Since September last year, United have gone 39 games unbeaten at Old Trafford, setting a new club record in the process.

Guardiola's men will be looking to bring that record to an end and to set one themselves, as they try to equal Arsenal's tally for most consecutive wins in the Premier League should they be victorious on Sunday.

Before focusing on the derby, however, United have to secure qualification for the knockout stage of the Champions League. A draw against CSKA Moscow at Old Trafford on Tuesday would be enough to progress as group leaders and Herrera says United are eager to get the job done, before focusing on City.

"I'm not thinking about Sunday, now it's about CSKA," he said. "We are not qualified yet so we don't think about City yet."