San Francisco 49ers safety Eric Reid has admitted that his side face a tough "challenge" when they face the Washington Redskins on Monday.

The Redskins' offense led by quarterback Robert Griffin III has been inconsistent this season but boasts a powerful rushing attacking as back Alfred Morris has 918 yards on the ground this season.

Reid told the club's official website: "We have to depend on our defensive line to keep him in the pocket, don't let him runaround out there. For the secondary, we have to stay tight in coverage so our defensive line can get to him.

"They have the No. 1 rushing attack in the entire league, so that opens up their play-action game really well.

It's a challenge for us. As a defense, we have to step up contain their run but at the same time don't give up the big passing play."

The 49ers have sustained back-to-back defeats and are 6-4 in their season going into week 12.