"The truth is I felt it a bit after playing in the game," the Frenchman told the Barcelona web site (www.fcbarcelona.com).
"It's not that I'm tired, but running around is one thing and playing football is another.
"Today was the first time since the start of March that I'd played, the first time in five months. I have to admit that it felt a bit strange and I still need time to adjust.
"But I'm delighted to got back to playing again."
Henry signed a four-year deal with Barcelona after completing a 24-million euro ($32.9 million) move from Arsenal last month.
The 29-year-old spent much of his final season at the London club on the sidelines after damaging stomach and groin muscles during his team's Champions League exit to PSV Eindhoven at the start of March.
The France international has been dogged by fitness problems ever since returning from last year's World Cup, suffering with a long-standing sciatic nerve pain, hamstring and foot injuries.
Barcelona are at a pre-season training camp in Scotland where they will play friendlies against Dundee United and Hearts before undergoing a promotional tour of the Far East.
Image: Ronaldinho (L) and Thierry Henry in training as Barcelona prepare for friendly matches against Dundee United and Hearts.