The 27-year-old striker finished off a route one move from the Barcelona-based team, latching on to a delightful through ball from Matias Vargas to lift over CSKA ‘keeper and captain Igor Akinfeev after a goal kick was headed on.
That goal made Lei the first Chinese player to score in European club competition, either in the UEFA Champions League or Europa League.
Although Lei netted a header after 149 seconds against Swiss team Luzern in August – the club’s fastest ever European goal – that strike came in the competition’s third qualifying stages, not the competitive stage of the tournament itself.
Lei has a habit of making history, already having become the first ever Chinese player to score in Spain’s La Liga when he netted against Real Valladolid during a home 3-1 at RCDE Stadium last season.
Espanyol won the game 2-0, bagging a second in injury after another direct move, pouncing when Anor Sigurdsson fumbled a header back to Akinfeev and subsequently gifted Victor Campuzano the chance to double the lead in the 95th minute.
The result means CSKA are rock bottom of the group and yet to record a victory in their two opening games, while Espanyol sit second with four points.