Arsenal goalkeeper Raya took heart from their battling performance as he looked ahead to the second leg at the Parc des Princes on May 7.
"They started quick with a goal, and they dominated the first 15 or 20 minutes, but after that, we dominated most of the game, created the chances. Donnarumma made some good saves," Raya said. "It's only half-time, we take positives.
Raya is convinced Arsenal, who knocked out holders Real Madrid in the quarter-finals, can defy the odds again as they bid to reach their second Champions League final and win the tournament for the first time.
"We showed from the 25th minute of the first half that we can win against any team. We have shown in the season we can win away games too, so we'll go to Paris next week trying to win," he said.