The British & Irish Lions may have kicked off their 2013 tour with a resounding eight-try win, but their performance showed plenty of hard work is required before the first Test against Australia on June 22.

In the end it was comfortable: 67% possession, 72% of the territory and hardly a lost line-out or scrum, or missed tackle. But in the heat and humidity of Hong Kong, Warren Gatland's side were far from fluent for much of the game, not helped by conditions every player described as the toughest they had ever played in.

But Gatland insisted: "It was a good run-out, exactly what we wanted and tougher than the score suggested.

"It was tough out there [the temperature ranged from about 25C to 30C during the game, the humidity from 65–80%], and the players said the ball was like a bar of soap, but everyone seems good afterwards, no knocks and no injuries."

It took the Lions almost half- an-hour to score their first try – and they had been playing against 14 men for much of that period after the Barbarians' Schalk Brits was sin-binned for punching his Saracens clubmate Owen Farrell, to which Farrell replied in kind.

"It's pretty hard sometimes not to react if someone lays a punch squarely on your jaw," Gatland said. "One of the things we are going to emphasise very strongly on this tour is to keep your discipline. It's a nice reminder that sometimes that happens and you need to take one for the team. You get whacked and you can't retaliate."

The experienced Paul O'Connell was the man who went over for the first try, making it 13-3 after a couple of early Farrell penalties, and for much of the game it was the players with previous Lions tours under their belts who kept the team in shape. Eleven made their Lions debuts over the course of the game.

"It was incredibly difficult," O'Connell said. "It's just hard to recover, you would be huffing and puffing. We were just saying it's great for us to have got that game under our belts and it will stand us in good stead going on with the tour."

The impressive Mike Phillips and another penalty from Farrell made it 23-3 to the Lions at half time, but there wasn't much value for the 28,643 souls who had braved exorbitant ticket prices to attend the historic first Lions game in Hong Kong. Luckily for them – and for Gatland – that changed after the break, as the Lions started to look more fluent and the strain of near constant defence started to tell on the Barbarians.

Phillips made an instant impact, showing great hands and pace just as he had for his first try. He was man of the match and stated an early case for Test inclusion. Farrell, however, may have done just the opposite, though his kicking was excellent. His fight with Brits will have been noted by sharp-eyed Aussies keen to test his temperament and his passing was far too loose.

One bad throw set the Barbarians on their way to their only try, Kahn Fotuali'i going over after flashes of his old greatness from Joe Rokocoko to make it 30-8.

Briefly, a challenge seemed possible from the Baa-Baas, who had completely wasted a week in Hong Kong by imposing a binge-drinking ban on themselves. But the final 25 minutes was all Lions, replacements such as Jonny Sexton, Conor Murray and George North making a big impact.

Jonathan Davies and Alex Cuthbert, with a double, stretched it to 47-8, then the forwards decided to get involved.

Richie Gray, the most impressive of the three Scots who played, all the more so considering it was his first game since March, helped drive a maul over the line, Dan Lydiate popping out of it for the try, before Alun Wyn Jones completed the rout at the death.

Much will be made of the wisdom or otherwise of the stop-off in Hong Kong, mostly by the English travelling press, who to a man seem obsessed with the fact that a tropical country is warm in summer. But the players will soon recover, and Gatland pronounced himself pleased.

"There was no-one I was unhappy with in terms of their performance, you've got to allow for the conditions," he added. "Players have said they caught the ball and went to pass it and it just slipped out. The disappointment is we conceded a try, but we can't complain. There's plenty for us to work on, but these players who have played tonight have laid down a marker."