Nantes is the Ligue 1 club that has had the longest unbeaten record in one season.
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Longest unbeaten run (all): Celtic currently hold the UK record for an unbeaten run in professional football : 62 games (49 won, 13 drawn), from 13 Nov 1915 until 21 April 1917- a total of 17 months and four days in all (they lost at home to Kilmarnock on the last day of the season).Longest unbeaten run (home): Celtic also hold the SPL record for an unbeaten run of home matches (77), spanning from 2001 to 2004 (this run was ended by a 3-2 defeat to Aberdeen on 21 April 2004), and the record for the longest run of consecutive wins in a single season (25 matches).
Celtic.
Chelsea
6,000,000,000 games unbeaten
Arsenal FC's longest streak was when they won the 2003-2004 English Premier League Season with an unbeaten record (38 games).
chelsea 86 matches
It is unknown which team has the longest unbeaten run in all competitions. Arsenal have the longest English league run with 49 games unbeaten, which included the entire 2003/04 Barclay's Premier League season unbeaten. Chelsea have the longest unbeaten home run in the league with 86 games. Liverpool have the longest unbeaten home run in all competitions with 85 games. The longest unbeaten League run in English Senior Football is held by AFC Wimbledon who went 78 games unbeaten from 22 Feb 2003 to 4 Dec 2004. This included a complete league season undefeated. Steaua Bucharest went 104 matches unbeaten between 1986 and 1989
The whole season
The answer is Arsenal FC
Spain and Brazil had 35 games unbeaten each. As of 06.28.10, Netherlands has a 21 game unbeaten run