In the first outing of their two-match South African tour, the Waratahs were outclassed 55-36 by last year's Super Rugby finalists in a comprehensive eight tries to five display.

A dominant Lions forward pack taught the Waratahs a lesson in successful scrummaging and mauling as they racked up try after try with relative ease.

Without three Wallabies in Bernard Foley, Nick Phipps and Will Skelton, the challenge of winning at South African altitude was always going to be an uphill battle for Daryl Gibson's men.

NSW backs were given more ball to play with compared to last week, but a whopping 36 missed tackles cost them dearly in what ended up being the fourth most points ever conceded by a Waratahs team.

"That's a horrific tackle stat but then I'm not going to take anything away from the Lions today," Gibson said. "They played particularly well, so credit to them.

"We'll take a great deal from today, there's a number of lessons for us. What I was pleased about is the fact we scored five tries, relatively easy. What we need to do is to sort out how to prevent tries."

The infamous 96-19 loss to the Crusaders in 2002, a 56-9 defeat to the Brumbies in 1997 and a 56-44 loss to the Blues are the only other times a Waratahs team has leaked more than 55 points.

NSW did not lead at any stage and were still a chance of victory when they trailed 43-29 with 20 minutes to go. However a seasoned Lions outfit prevailed to hand the Waratahs their first loss of 2017.

"We like coming to South Africa but the Lions were too good tonight," said Waratahs captain Michael Hooper. "It is a tough place to play. We don't make excuses for ourselves, but we want to come over here and win and we didn't do that so we'll go next week again against the Sharks."

Asked what the team needed to work on most before their next game in Durban, Hooper said: "Defence. Their high-ball chase is big up here so just working hard off the ball is the big improvement we want to work on."

Even from kick-off the Waratahs were under immense pressure from a dominant Lions driving maul.

"That's an area of concern for us in terms of how easy we conceded there," Gibson said. "The Lions had a very good maul, and we've got to work out a way to defend a maul more successfully."

NSW conceded an early try but hit back minutes later with their first attacking passage of the match.

Fullback Andrew Kellaway threw a neat dummy, which saw him squeeze into space before passing to Rob Horne who did the rest on the left edge.

After 10 minutes and with scores level, Waratahs winger and first-choice goal-kicker Reece Robinson was sent to the sin bin for a spear tackle in a minor brain snap. It was unintentional, but careless nonetheless and may catch the eye of match officials.

Both teams then traded tries through Ruan Ackermann and Michael Hooper before the hosts scored another three in a row to open up a healthy 16-point point advantage.

The NSW cause wasn't helped when Sekope Kepu became the scapegoat for multiple infringements and was sent to the bin for the second straight match.

The Waratahs scrum was no match for the Lions, whose driving maul was a key feature and their ability to build continual pressure through favourable field position.

Deep kicks into Waratahs territory made it difficult for them to get out of their own half, particularly when lousy kicks close to their own line failed to relieve any pressure whatsoever.

New No.10 Bryce Hegarty was guilty of a number of these but made up for it with a brilliant chip and chase in behind a number of tired forwards to get the scoreline to 33-24 at half-time.

Eight tries were scored in the first half alone - four times more than in last week's dull 80-minute affair between the Waratahs and Western Force.

The frustrating thing for the Waratahs was that whenever they got the ball in hand, they looked dangerous, and would have been thrilled to turn their 28 per cent of first half possession into 24 points.

Kellaway had one of his best games in a Waratahs jersey, with five nippy runs for 102 metres including four tackle busts, while blindside breakaway Jack Dempsey carried the ball up with little regard for safety in an eye-catching performance.

A 50th-minute drop goal to Elton Jantjies put the Lions ahead by 12 points before Rohan Janse van Rensburg's second of the match put the Waratahs more or less out of striking distance.

David McDuling and Israel Folau got themselves on the scoresheet in the 59th and 80th minutes, but it was too little too late for the Waratahs after the leaking an uncharacteristic number of points and they will know they have plenty to work on.

Fairfax Media