BOSTON — Thomas Castellanos threw for 234 yards and four touchdowns in the first half before new Boston College coach Bill O’Brien went to his bench Saturday as the Eagles followed up their upset of then-No. 10 Florida State by routing FCS Duquesne, 56-0.

Darius Perrantes completed 8 of 18 passes for 62 yards and two interceptions for Duquesne (0-2).

Castellanos completed 9 of 10 passes, including TDs of 72, 49, 30 and 4 yards — all to different receivers. Lewis Bond caught five passes for 98 yards and a 49-yard TD — all in the first half — and Reed Harris caught a 72-yard score.

After going nowhere on its first drive, BC (2-0) scored touchdowns on its next five possessions — and added Khari Johnson’s pick-6 — to end the first half with a 42-0 lead.

Backup quarterback Jacobe Robinson came on to start the second half for the Eagles and fumbled on his third play before BC took a 49-0 lead on a 47-yard run by Datrell Jones. Robinson ran it in from 9 yards in the final minutes to make it 56-0.

Treshaun Ward ran for 55 yards and a touchdown, also all in the first half. Freshman Turbo Richard ran for 74 yards in the second for the Eagles, who opened O’Brien’s tenure with his hometown school by beating the Seminoles, 28-13, in Tallahassee last week.

After opening against two FBS programs, the Dukes get back to the FCS when they visit Youngstown State.