Shamir Goodwin gave the visitors the lead but Eoin Doyle quickly equalised and O'Shea clinched victory with goals in the closing minutes to leave Torquay still without a league win at Chesterfield.
Chesterfield almost scored in the third minute when Jay O'Shea got in on the right but his angled drive came back off the underside of the bar and Torquay settled to create an opening for Anthony O'Connor which he volleyed wide.
The rest of the first half was forgettable but the game came to life in the 50th minute when Goodwin broke from inside his own half and ran clear down the right before firing past Tommy Lee from 15 yards.
Chesterfield responded by equalising six minutes later when goalkeeper Michael Poke's clearance struck a defender and sent Doyle away to score with a low shot.
Torquay should have regained the lead in the 78th minute but Conor Wilkinson shot wide from eight yards after Goodwin had struck a post and two minutes later O'Shea burst forward to score from the edge of the area before striking again deep in stoppage time.
- Sports & Recreation
- Eoin Doyle