Legendary former Gunners boss Arsene Wenger led Arsenal to the Premier League title in the 2003-04 season without suffering a single defeat in England's top-flight league.
However, the iconic Arsenal team failed to capture the Champions League trophy in the 2003-04 season.
Arsenal brushed aside Celta de Vigo in the round of 16 before facing London rivals Chelsea in the quarter-finals.
The Gunners' first-leg clash at Stamford Bridge ended in a 1-1 draw, but the second-leg tie didn't end in Wenger's favour.
Arsenal crashed out of the Champions League in a 2-1 defeat at Highbury.
The London club went into half-time with a 1-0 lead, but Chelsea legend Frank Lampard pulled back an equaliser for the Blues early in the second half.
Wayne Bridge's left-footed finish beat Jens Lehmann in the 87th minute to condemn Arsenal to a 2-1 defeat on the night.
FourFourTwo compiled the rankings and placed the Invincibles top of the pile ahead of Jose Mourinho's 2004-05 Chelsea side.
Juventus (1996-99) finished third in the rankings, while Atletico Madrid (2013-14 and 2015-16) ranked fourth and Valencia (1999-2001) came fifth.
Atletico's 2013-14 and 2015-16 sides both reached the Champions League final, only to lose to arch-rivals Real Madrid on both occasions.
Posted below are FourFourTwo's picks for the 10 best teams that didn't win the Champions League.
10. Ajax (1995-97)
9. Juventus (2014-19)
8. Barcelona (1993-96)
7. Borussia Dortmund (2012-2013)
6. Inter Milan (1998-99)
5. Valencia (1999-2001)
4. Atletico Madrid (2013-14 and 2015-16)
3. Juventus (1996-99)
2. Chelsea (2004-05)
1. Arsenal (2003-04)
Featured Image Credit: PA
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