When Mayor Bill de Blasio launched universal pre-K in 2014, he said it had “taken the dedication of an untold number” of supporters and that his administration had “pushed so hard” to make it happen.

But on Friday, he appeared to downplay his signature education achievement as he faced questions about why the rollout of a new low-income transit program, called Fair Fares, went over its Jan. 1 launch date and won’t be immediately accessible to every low-income New Yorker.

“When we came in, there were about 20,000 kids in full-day pre-K,” de Blasio said when a reporter asked him how his administration was able to roll out the “massive” universal pre-K program in under a year.

“Over a two-year timeline we got it up to 70,000, but it was based on an existing application and the parameters were already known,” he said.

His comments raised eyebrows as observers noted how massive a lift universal pre-K required.

Fair Fares, de Blasio said, is a brand-new program and important details had to be hammered out — like determining the parameters and rooting out potential fraud by making sure the program reaches those who are eligible.

“There were a lot of things we had to put into place that were from scratch that just weren’t true with a program like Pre-K,” de Blasio said.

City Council Speaker Corey Johnson added that Fair Fares could potentially reach 800,000 people — far greater than the 70,000 children who are enrolled in universal pre-K.

De Blasio’s downplaying of the pre-K rollout stands in stark contrast with his past language. When de Blasio’s administration officially expanded pre-K, officials described the move as monumental — “the largest and most ambitious expansion of pre-K of any city in the nation’s history.”

Within nine months of expansion efforts launching, about 31,500 four-year-olds were registered for pre-K programs — a little more than the number of New Yorkers who will have first access to half-priced Metro cards under Fair Fares after six months of work.

Also in that nine-month timeframe, 1,655 public schools and community-based early childhood centers were ready to provide pre-K programs with 1,000 new pre-K lead teachers, according to the city’s announcement in 2014. Fire, health, buildings, and education officials conducted inspections and site visits to 6,000 pre-K centers the summer before the September 2014 launch.

The de Blasio administration is continuing to expand pre-school for three-year-olds and plans to offer it through a dozen districts by 2020.