Ireland finished second in the group which sees the side progress to the elite round stages of the competition next year despite defeat in the final qualifying round game to the host nation Serbia.
Colin Bell's side were dominant throughout the game but failed to find the net as the only goal of the game came in the 12th minute.
Krstina Tanasković found space just outside the area and arrowed her strike into the bottom corner to seal the victory for the table-topping side, despite huge second-half pressure from Ireland.
Ireland had 12 attempts in the second-half as Emily Whelan, Rebecca Cooke and Emily Whelan all saw their efforts go close. With three minutes remaining, Shelbourne Ladies' Jessica Ziu hit the post as Serbia's narrow advantage remained intact to condemn Ireland to defeat.
"We're obviously happy to get qualification but disappointed with the result. We were the better team throughout the game and couldn't get the goal we deserved," said WU17 Head Coach Colin Bell.
"It was the most physical game we've had so far so the players will learn from the defeat. We just made the wrong decision at crucial times but we absolutely dominated and the players can be proud of the way they played.
"There are a lot of positives to take from the three games. The squad has made fantastic progress over the course of the week and showed a willingness to learn and improve which is important.
"We had a few injuries before we came out here and suffered injuries against Albania and Wales so the squad have dealt with that really well. It's important that we continue to work with the squad to keep improving ahead of the next phase."
The elite round draw will take place on Friday, November 23 in Nyon with the fixtures set to take place in spring 2019.
Republic of Ireland: Courtney Maguire (GK), Shauna Brennan, Mia Dodd, Ellie Ferguson, Jessica Ziu, Eabha O'Mahony (C), Emily Whelan, Rebecca Cooke (Lauren Egbuloniu 90), Emily Kraft, Katelyn Keogh (Sophie Liston 84), Therese Kinnevey (Aoife Horgan 88).
Serbia: Tatjana Perenčević (GK), Lena Marjanović, Isidora Gajdobranski (C), Milica Denda, Nikolina Milić, Margita Vasović, Zivana Stupar (Helena Host 74), Emilija Ema Petrović, Nina Čavić (Anastasija Ćirić 57), Krstina Tanasković (Milica Beronja 90), Teodora Stojaković (Dejana Magovčević 73).
Referee: Iuliana Demetrescu (ROU)