The club's record signing and last season's 25-goal top scorer sat on the bench alongside Bruce after being left out of the squad, with Kenwyne Jones the lone striker in a 4-5-1 formation.

But the manager was quick to reassure fans about the hitman's wellbeing.

He said: "Darren's fine, but he's got a couple of minor niggles and it wasn't worth risking him.

"The situation did at least allow us to experiment with a 4-5-1 formation and explore that.

"It was a good game and it has been a good trip."

Bruce revealed that Jones's knock, which forced him off in the 35th minute, is nothing serious.

"He's twisted his knee a little, but he'll be fine," he said.

Bruce works his players hard in pre-season, demanding a high level of fitness for the start of the campaign. The Black Cats wrap-up their summer schedule with games at Championship side Leicester on Saturday and away to German Bundesliga outfit Hoffenheim on Sunday week.

Bruce said of the Portugal camp: "We've got through so much good work in terms of fitness training.

"We went to the same training complex last year and it was great for us and that's why we were happy to come again.

"This summer, it has been even more successful if anything, just because we were a little more familiar with the place.

"I'm very pleased at the fitness work we've done and we're flying home with the squad much better prepared for the challenges ahead.

"I'm happy that after the games against Leicester City and Hoffenheim, we'll be ready for the season to begin."