I don't think there's much riding on this game other than the Giants winning their 90th game of the season and perhaps Tetsuya Utsumi winning his 10th game of the year to keep his string of double-digit wins intact.
If the Giants win their 90th game of the year tonight, they do it for the first time in 44 years. And if Utsumi wins tonight, he'll become only the 4th left-handed pitcher in team history to record four consecutive seasons of 10 or more wins.
For the Swallows, this could be a preview of what's to come in the second round of the Climax Series. To that end, this game probably means more for the Swallows than it does for the Giants. They will also be sending Yoshinori Sato to the hill for this 6th start against the Giants. Yoshinori has largely been ineffective against the Giants this year (28 IP, 31 H, 8 BB, 19 R, 14 ER) so this could be a good test for him.