Ireland had kept three clean sheets in the pool stages of the tournament but that impressive streak was breached in the first quarter as the USA took the lead.
A turnover in their own half by Ireland allowed Zimmer to run into the circle and fire the ball low, and into the far corner of Ayeisha McFerran’s net.
Ireland thought they had equalised just before the end of the opening quarter but Mikayla Power’s goal was disallowed after Mullan was adjudged not to have moved the ball the required five metres from a free hit before entering the circle.
The goal was not long in coming, however.
In a dominant second quarter, Upton converted a penalty stroke after an effort from Niamh Carey was blocked on the line by an American foot.
The third quarter was a tighter affair but was highlighted by Mullan’s goal.
Elena Neill’s superb ball into the circle was instantly controlled by Mullan, who then beat her defender and got the shot away and it ended up in the USA net.
The final 15 minutes were not without a scare or two for Ireland and they had to defend bravely after a five-minute yellow card to captain Sarah Hawkshaw and a two-minute green card to Mullan.
It’s the second consecutive year Ireland have reached the Nations Cup final. After losing to Spain they’ll be hoping for a different result on Sunday.
