Atletico Madrid's defense of its Europa League title got off to a bad start Thursday, losing 1-0 to Aris due to Spanish midfielder Javito's second-half goal.
Javito controlled the ball with his chest between two defenders before firing past goalkeeper David de Gea to score a classy goal in the 59th minute in the Group B match.
Aris captain Sergio Koke rattled the post with a powerful shot 10 minutes later. He also had a shot cleared by De Gea in the 81st.
"I'm really happy. It was a great win and it felt great to score the goal," Javito said. "When I scored, I just went crazy. All I wanted to do was run toward the fans and celebrate."
Atletico striker Diego Forlan, who scored both goals for his team in the 2-1 win over Fulham in last season's final, was heavily marked and could only shoot wide twice in the first half.
Atletico substitute Diego Costa missed with two headers in the 78th and 79th minutes.
