The City forward, who grabbed a hat-trick in their tournament opener, started the match on the bench for the Young Lionesses as they looked to guarantee qualification for the knockout stages.
However, Nina Matejic’s opener midway through the second half meant Pritchard and co. had a mountain to climb in Lithuania.
Matejic’s strike, an impressive solo effort and finish, sprung England to life with Pritchard forcing a save at the near post from a tight angle soon after.
She went close again with five to play, seeing a vicious volley on the turn blocked off the Serbian line, before play was pulled back for a foul.
But England’s pressure eventually paid off when they were awarded a late penalty when Vivienne Lia’s attempted ball into the box from the left was blocked by the elbow of Milica Stojic, much to the bemusement of the Serbian defender and her team-mates.
Mia Enderby stepped up to do the honours from the spot, maintaining the Young Lionesses’ unbeaten start to the tournament and moving them within touching distance of the knockouts.
England’s vastly superior goal difference, helped by Pritchard’s treble in their 10-0 win over Lithuania, means only a heavy defeat against France, and an emphatic win for Serbia, would prevent them from reaching the semi-finals.
The Young Lionesses face the French in their final group fixture on Saturday 20 July, with kick-off set for 16:00 (UK).
