But the Bulls should have settled matters in normal time after an injury-time leveller from Orient ensured the encounter finished 1-1 after 90 minutes.
Trewick said: "Conceding a goal 20 seconds from the end was a kick in the guts. Before we set off and in the team talk we said a draw might be good enough.
"You always fancy Adam to save a penalty and sure enough he came up trumps. He is really athletic and has a system although he won't tell anybody what it is, but it works."
Trewick also lavished praise on Gavin McCallum. He said: "He's a lad who has been working very hard in training and I thought he did really well. He deserved his opportunity and ran his socks off in the second half when he was up there on his own. He can be delighted with his performance."