Roy continued his impressive white ball form for England with 85 runs as the World Cup hosts made light work of Australia in the semi-final.
England excelled with the ball in hand after Australia chose to bat first at Edgbaston and Finch’s side were held to 223 runs after 49 overs.
England have long struggled to find a stable opening Test partnership and it still remains uncertain who will be lining up to face Australia in whites on 1 August at Edgbaston.
Roy continued his fine partnership with Jonny Bairstow and took his World Cup runs tally to 426 spread across seven innings, and Finch expects his Surrey teammate to open for England in a few weeks when The Ashes starts.
“He definitely goes hard having played with him for a few years now for Surrey,” Finch said. “He's a player that when he's on he can be so damaging to an opposition and in such quick time as well. So not sure what the wickets are going to be like in the Ashes series. I think the first Test is here, is that right? So, it will be interesting to see how that plays out.
“But he's got some really good hundreds in county cricket, probably more so in the middle-order. That is just one of those things that if he gets going on his day, he can be brutal and he can score so quick in all forms of the game, he is a very dangerous threat no doubt.”
In an exclusive interview with The Independent ahead of the World Cup, Roy revealed he hopes his one-day form can earn him a place in the Test side.
"My main focus is on the World Cup, looking to play the best cricket possible and hopefully win it,” he said. "That is the best way to push my case, if I score the volume of runs that I want to score then I'll get myself noticed."
Finch added that he expects Australia to face hostile crowds during The Ashes series this summer, especially at Edgbaston.
“The atmosphere -- they appreciate good cricket as well as obviously supporting England heavily. But they do appreciate good cricket. It is great fun playing here. It's -- no doubt throughout the Ashes series it will be loud as well wherever you go.”
As for Australia’s defeat in the semi-final, Finch admitted they were second-best against England throughout the entire game.
“We were totally outplayed to be honest all throughout the day, so you look back at that and you can analyse each ten overs, but just outplayed.
“We came here today expecting to win,” he added. “We felt like our preparation leading in to the tournament and then the momentum we'd built-up through the tournament was really important and we came here feeling good, we trained well, we had enough break in between games and guys were fresh enough, so very disappointing.”
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