The 33-year-old's contract was due to expire on June 30, having joined the Gunners last summer from Chelsea on an initial 12-month deal.

Luiz's new agreement comes despite heavy criticism following his display against Manchester City last week, when he was at fault for two goals - conceding the penalty that led to the second - and was sent off.

Arsenal have also moved to make the temporary moves of fellow defenders Pablo Mari and Cedric Soares into permanent arrangements - from Flamengo and Southampton respectively - while midfielder Dani Ceballos' loan from Real Madrid has been extended until the end of the 2019-20 season.

"David is a really important player for us," technical director Edu told the club's website. "He has played most of our matches this season and has been important for the team. His passing, his communication with the team on and off the pitch. He helps everyone."

Australian Associated Press