The Poachers succumbed to higher-grade opponents on their artifiicial pitch.
This FA Cup replay was always a tough task but Martyn Bunce’s side bowed out with their heads held high.
Williams gave the hosts an early lead, before Jordan Nuttell came close to equalising.
At the interval, with the score only 1-0, the visitors were still in the tie – but an Ireland penalty at the start of the second half gave the Poachers a mountain to climb.
Ireland completed his double after 69 minutes to send Harborough through the Preliminary Round.
Town: Portas, J Tate, Field, Wilson, Ford, Adams, Young, Maddison, Nuttell, Limb (L Tate), Bayliss; unused sub: Beeson
Boston Town FC 