First, 姜華珺 is not young, she has over 30s. We cannot expect her performance can be as well as twenties.
The most important, the main reason may te that the 3rd palyer of HK Women team is weaker than other countires' 3rd players. She palyed all the matchs in the Group Competition, but only won once - the least match against the weakest team of the Group Competition.
Therefore, 帖雅娜 and 姜華珺 must win 3 games to ensue the Hong Kong's victory. It not only give them high pressue, but also consume more energy.
See the overall results of the Group Competition belows:
Hong Kong 3:2 Czech (帖雅娜 got 2 points and 姜華珺 got one)
Hong Kong 3:2 Austria (帖雅娜 got 2 points and 姜華珺 got one)
Hong Kong 2:3 Russia(帖雅娜 got 2 points)
Hong Kong 3:2 Korea(帖雅娜 got 1 point and 姜華珺 got two)
Hong Kong 3:0 Croatia(帖雅娜 got 1 point, 姜華珺 got one and the 3rd player got one)
帖雅娜 played 9 matchs: 8 win and 1 lost (victory rate 91%)
姜華珺 played 9 matchs: 5 win and 4 lost (victory rate 56%)
The 3rd player played 5 matchs: 1 win and 4 lost (victory rate 20%)