Arteta left out Declan Rice on his return to the London Stadium, with the England international alongside Bukayo Saka, Martin Odegaard and William Saliba on a star-studded Arsenal bench.
Liverpool manager Jürgen Klopp made 11 changes in his starting lineup from the 3-1 comeback victory over Wolverhampton on Saturday in the English Premier League.
It took the champions just 40 seconds to level after the break. Doku received the ball wide near the left touchline and looked up to find little on inside the box.
Argentina midfielder Enzo Fernandez missed a penalty that would have put Chelsea 2-1 up just before the halftime break.
Álvarez, who won the Dutch league twice with Ajax, joins a club that will play in the Europa League this season after winning the Europa Conference League.