BERLIN, Sept. 23 (Xinhua) -- German Chancellor Angela Merkel's conservative Christian Democrats (CDU) and their Bavarian sister party, the Christian Social Union (CSU), emerged as the biggest winner in Sunday's federal election, official provisional results showed early Monday.

The pair garnered 41.5 percent of the vote, while the largest opposition party, the center-left Social Democrats (SPD), took 25.7 percent, according to the results.

The Green party, the SPD's favored ally, captured 8.4 percent, and the Left Party got 8.6 percent, showed the provisional results.

Merkel's junior coalition partner, the Free Democrats (FDP), however, failed to retain its seats in the parliament, with its disappointing share of 4.8 percent falling short of the 5-percent minimum needed to enter the parliament.