A brace from Reading's Alex Danson saw Great Britain secure a 2-1 victory over Japan at the Olympic Park in Stratford.
The Cherry Blossoms took a first-half lead through Yukari Yamamoto before GB retaliated in the second half.
The match was seen as an important warm-up before the Olympic qualifying event in June, when GB will travel to Spain to play in the World League for a place at the Rio 2016 Games.
The two sides play again on Monday to complete their two-Test series.
GB skipper Kate Richardson-Walsh broke her jaw against Japan in their opening match of the 2012 London Olympics.
However there was no such drama on Sunday as the two sides met once again, the first outing Great Britain's women have had at the new Lee Valley Hockey and Tennis Centre since it opened in 2014.
GB started strongly and enjoyed the majority of possession before a smart attack by Reading teammates Danson and Susie Gilbert saw them awarded the first penalty corner of the match.
|Alex Danson in numbers|
|Age: 29||Goals: 78 (England - 47 & GB 31)|
|Caps: 231 (England - 165 & GB - 66)||Medals: 3 (1 Olympics & 2 Commonwealth)|
The GB set-piece routine failed to find the target and the first quarter finished 0-0.
In the second quarter the Cherry Blossoms won their first penalty corner and when the ball hit a British player's foot the umpire awarded a penalty stroke that was dispatched by Yamamoto.
GB and Holcombe keeper Maddie Hinch managed a vital save as the ball flew towards goal through Mie Nakashima.
But after Japan were unable to convert their second penalty corner opportunity, GB started to dominate.
And GB's top-goal scorer Danson soon rounded Japan keeper Ryoko Oie to find the target.
Credit must go to Helen Richardson-Walsh, who passed to Danson - the 33-year-old Richardson-Walsh was making her 250th international appearance after a year away from the sport recovering from a back injury.
The final quarter saw the home side awarded a penalty corner with less than three minutes left to play.
And the cleanest penalty corner routine of the match saw Danson slot home her second of the game.
There was a clear smile across the face of GB coach Danny Kerry at the final whistle with victory over the team ranked tenth in the world ahead of the Olympic qualification period.