Joe Root has full confidence in England's ability to bounce back from consecutive defeats and progress to the Cricket World Cup semi-finals.

Australia piled the pressure on the pre-tournament favourites with a 64-run victory at Lord's on Tuesday on the back of the hosts' surprise 20-run loss to Sri Lanka at Headingley.

That setback has left Eoin Morgan's top-ranked side on eight points, looking nervously over their shoulders with tough clashes against India and New Zealand to come.

Test captain Root says England are backing themselves to seal a top-four finish.

"We've still got two games so it's in our hands. Two very big games, but we're not out of this competition," Root said. 

"We've got to look at the stuff we’ve done well up to this point and take that into the two final games.

"It doesn't make us a bad side overnight, having played how we have in the last 100 overs.

"We've just got to make sure we stay true to what we've done so well over a long period of time, and keep looking to do the basics well, like building big partnerships with the bat and striving to take early wickets.

"It's not all doom and gloom. We just have to be at our best in the next two games. We're a very strong side. That doesn't change off the back of two games and we've got to keep trusting all of the stuff that has served us so well."

James Vince has failed to grasp his opportunity in the absence of Jason Roy due to a hamstring injury, but Root has defended his fellow batsman.

"Just because James hasn't scored runs doesn't make him a bad player," Root said. "If Jason isn't fit, I'm sure Vincey will be determined to go out and get a big score and bat very strongly.

"Jason's obviously a fine player who has done some incredible things in an England shirt, so it would be great for him to be around, but I fully believe the guys who played [against Australia] are a very strong side that is more than capable of winning the next two games."