- Tag results for Atletico Madrid
The visitors had fallen behind against the run of play in the 18th minute when winger Samuel Grandsir forced the ball home in a goalmouth scramble after good work from Radamel Falcao.
Griezmann had teased Ramos after Atletico beat Real Madrid 4-2 to win the UEFA Super Cup in August.
In the 2016-2017 season Monaco beat Manchester City and Borussia Dortmund before losing to Juventus in the semi-finals, with club owner Dmitry Rybolovlev then selling a raft of stars.
Atletico Madrid star Antoine Griezmann says he still can't fathom why he was not voted one of the world's top three players by FIFA.
For Griezmann, who helped Atletico to Europa League glory as well as playing a pivotal role in France's World Cup win, FIFA's choice was unwarranted.
Seven points is now the gap between Atletico Madrid and Barca, who were in danger of slipping up themselves when Aritz Elustondo put Real Sociedad in front at Anoeta.
The Madrid side had 18 shots in total, but Antoine Griezmann and Diego Costa were both wasteful and as the game wore on, Eibar's confidence grew.
Diego Simeone said that he is used to the pressure, adding that results are always the key to change a difficult situation.
Atletico Madrid did not specify Arias's expected recovery period, although this type of injury requires at least two weeks off the field.
Rejuvenated under new coach Julen Lopetegui and, perhaps, liberated by Cristiano Ronaldo's departure, Bale and Benzema impressed again.
Barcelona skipper Lionel Messi struggled to make an impact on a dreadful pitch that kept cutting up.
Atletico were given a tough test to start the campaign at a strong Valencia outfit who will be playing in the Champions League this season for the first time since 2015 after finishing fourth.
Simeone's men then looked stronger in the extra period as they won this competition, the annual meeting of the Champions League and Europa League winners, for the third time in nine seasons.
So far, Madrid hasn't resorted to a "galacticos" spending spree to bring in marquee names at astronomical prices.
The 30-year-old only joined Milan on a permanent contract in July after spending last season on loan at the San Siro from Fiorentina.