Dave Bell's group face Norway tomorrow in their second Group B match of the UEFA Women's Under-17s European Championships at the Doosan Arena, Plzen with kick-off at 11am (10am GMT).
Ireland suffered a 5-0 defeat in their opening group game against a strong England side, as Ireland wasted a number of opportunies throughout the first-half in their opening match.
Ruddy, who missed the defeat through suspension, is ready and raring to go to help Ireland put their qualification hopes back on track with an all-important win.
The WU17s captain said: "It's a huge game for us and we know we've got to get a result tomorrow which I think will help us focus ahead of the game.
"It is always easier to know what you've got to do ahead of a match and training has been really good so I'm really confident of getting the result we need tomorrow.
"We've seen Norway in the clips and they're a good side but we know if we can play to our very best, we can beat them and that has to be the mentality going into the match."
Norway also lost their opening Group B match, a 3-1 defeat to the Netherlands so both sides know that they need a result to keep their qualification hopes alive.
Having worked with the medical staff to overcome a hamstring problem, Ruddy is determined to make the most of the European Championships experience.
She added: "It was great to be back in training as I've been out of it for a couple of weeks but I've really enjoyed the past couple of days.
"The squad have really responded in the right way in training as it was difficult to watch the England game from the stands. We should have taken our chances in the first-half of the half so we know that 5-0 isn't showing what we can really do.
"We're looking forward to putting that right tomorrow and if we can get a win, it puts us in a good position to qualify going into the final group game."