The Republic of Ireland beat Scotland in a World Cup play-off two years ago, while the Welsh are aiming to qualify for a major tournament for the first time.
Irish defender Denise O’Sullivan had a debut to remember against Wales in 2011 as the midfielder netted a double in a 2–0 win in a Euro qualifier in Newport.
She hoped to get another positive result to bring back for the second leg in Dublin on Tuesday night.
“No matter what happens, we still have that second leg at home and we’ll have that home crowd behind us,” added O’Sullivan. “That’s the only thing I’m thinking about, full focus is on Friday night now.
“We know it’s a lot of pressure but I think we’re more prepared than ever and we can handle that. I think the only conversations we’re having is how excited we are, how prepared we are for this game against Wales. We’re all looking forward to it.”