The Pirates finished the year with a 98-64 record, the second best in all of baseball. That ties them with the 1979 and 1908 clubs for the third most wins in franchise history. (The 1909 Pirates won 110 and the 1902 club won 103.) The Pirates' record, however, included a losing record against two of the worst teams in the game, the Cincinnati Reds (8-11) and the Milwaukee Brewers (9-10).
Let's break that down. In games in which the Reds didn't play the Pirates, they were 53-90. In games in which the Brewers didn't play the Pirates, they were 58-85. So in their non-Pirates games, the two clubs combined for a 111-175 record, a .388 winning percentage. Had they played at that pace in their 38 games against the Pirates, they would have won .388 x 38 games = 15 games, losing 23. Turned around, the Pirates would have gone 23-15 against the Reds and Brewers.
The Pirates were 81-43 in their games that weren't against Cincinnati or Milwaukee. Had they gone 23-15 against the two clubs--that, is had they been as successful as the rest of the teams in the majors were--their record would have been 104-58. That would have given the Pirates the best record in baseball. They would be enjoying four off days, looking forward to Wednesday's wild card game between the Cardinals and Cubs to see whom they'd face at home to kick off the Division Series on Friday.