Could a diesel submarine outmaneuver a nuclear fleet?

Could the diesel submarine plot in Down Periscope succeed against a nuclear fleet?

Yes; real exercises used comparable matchups, and demanding opposition was valuable for testing nuclear forces honestly.

The central exercise in Down Periscope is plausible because real naval exercises used comparable matchups between conventional submarines and nuclear forces. Difficult opposition gives a force a demanding test. Rigging an exercise to guarantee the nuclear force's success would undermine that purpose.