Captain Alun Wyn Jones suffered an early injury blow before three British and Irish Lions debutants scored tries in a 28-10 defeat of Japan at Murrayfield.
Jones was withdrawn in pain in the eighth minute of the first-ever Lions Test in Scotland on Saturday with what was reported to be a shoulder injury.
Justin Tipuric was also forced off with an injury in the first half of the Lions' first meeting with Japan ahead of the tour of South Africa, which Warren Gatland's side won comfortably to lift the 1888 Cup.
Josh Adams, Duhan van der Merwe and Tadhg Beirne marked their debuts with a try, while Robbie Henshaw also touched down and the excellent Dan Biggar was on target with all four conversions.
Japan, playing their first Test since losing to the Springboks in the quarter-finals of the 2019 World Cup, entertained in the second half and were rewarded with a try from Kazuki Himeno.
There was concern for the Lions when skipper Jones was replaced early on after doing damage while trying to turn the ball over before his Wales team-mate Adams got the first points on the board.
The winger showed great feet and good strength to come in off the line and power his way over following a strong run from Bundee Aki.
Tipuric also made a concerning early exit before Van der Merwe caught Japan napping, picking the ball up from the back of a ruck and crossing all too easily.
The Lions were dominant and Ireland centre Henshaw ploughed over from close range after taking a pass from Conor Murray, with the impressive Biggar's third successful conversion increasing the lead to 21-0.
Courtney Lawes, Jones' replacement, lost control before grounding the ball when he crashed over early in the second half, but Beirne took a great line and showed a sharp turn of foot to burst through and go under the posts.
The Brave Blossoms enjoyed themselves after the break and Himeno finished following a lineout routine as the Lions defence work given a great workout with bigger tests to come.
Lions wait on Jones and Tipuric
It takes a lot to keep Jones down, so the sight of the lock grimacing on the deck and taking a rueful look to the skies was a worry for the Lions.
Gatland faces an anxious wait to discover the extent of the most-capped player in Test history's injury before the Lions board the plane to South Africa.
Flanker Tipuric's involvement was also brief just under a month before the first Test against the world champions in Cape Town.
Wales winger Adams and Scotland flyer Van der Merwe wasted no time in marking their mark on their Lions bows.
Van Der Merwe, the leading try-scorer in the Six Nations this year, made 72 metres from eight carries and beat four defenders.
Adams did not see as much of the ball, but grasped his early chance, while Beirne made 49 metres from his 10 carries and won two turnovers in an eye-catching display.