Arsenal sent their scouts to watch Benfica left back Alex Grimaldo last weekend as his side routed Nacional 10-0, according to the Mirror.
The Gunners scout was in the stands to watch the full back in action according to Portuguese publication A Bola, and would have been impressed with what they saw from the start of the match.
The former Barcelona academy product set his team on their way to an emphatic win with an impressive goal in the very first minute.
The Gunners are currently in search of a long-term replacement for aging defender Nacho Monreal and have identified the 23-year-old as a potential replacement.
However, the Gunners will face stiff competition as he has also attracted the attention of Manchester United and Atletico Madrid who are in the hunt for his signature.
The Gunners are in dire need of defensive reinforcement with the future of trusty and consistent veteran left back Monreal in doubt and back up Sead Kolasinac failing to inspire confidence in defence over time.
The centre back and right full back positions has also been riddled with injuries and loss of form of several players, with Monreal now having to fill in at centre back sometimes.
The Gunners are bound to spend in the summer to fix their defense and Grimaldo will be on the top of their list.