Frail praised his side for the way they commemorated a "special" day in the club's history with a thrilling 4-1 victory in front of owner Vladimir Romanov.
Romanov was in the stand at Tynecastle for the first time this season and was rewarded for his visit with a magnificent display from his team.
Staff and players, who for the meeting with the Dons wore special commemorative strips featuring a red poppy and the names of the Hearts players who died in the First World War, gathered at the Haymarket war memorial in the city before seeing off Aberdeen.
Frail said: "I was delighted with the game. It's a special day for the club, with the memorial service we have every year for the Hearts players that fell in the First World War.
"All the players turned up to that, the whole squad and the whole club, and to go and put on a performance like that, I am delighted.
"Lots of things pleased me - the tempo they played at, the way they stuck to all the things that were set out for them before the game, the way we passed the ball and moved, the chances we created and goals we scored. It was a good day.
"It let Mr Romanov see first hand that everyone at the club, staff and players, are all pulling in the same direction.
"There was a real team spirit about the whole day, with where we were this morning, the strips the players wore in the first half. It all contributed, in my opinion, to getting the victory."