Arsenal are in talks to sign Sporting's prolific Sweden striker Viktor Gyokeres for &163;70m.
As first revealed by BBC Sport on Thursday, Arsenal have had a clear focus on completing a deal for the 27-year-old in recent days and the club are now advancing in their pursuit of the forward.
Discussions over personal terms for Gyokeres and with the Lisbon club over a transfer fee are accelerating, with Arsenal's sporting director Andrea Berta leading negotiations.
A deal has not been finalised though, and there remains a degree of caution at Arsenal until agreements are reached.
Gyokeres has been heavily linked with a move to the Premier League after scoring 97 goals in 102 matches during two seasons in Portugal.
The Gunners completed the &163;60m signing of Martin Zubimendifrom Real Sociedad on Sunday.
But the movement towards a deal for Gyokeres represents a significant development in Arsenal's summer transfer business given a new striker was the club's main priority.
Gyokeres' task is clear - analysis
Sami Mokbel, senior football correspondent
It appears Viktor Gyokeres will be the man Mikel Arteta will rely on to make the difference next season.
Arsenal's critics are adamant the club's title challenge foundered last season because of their lack of an elite forward.
If Gyokeres arrives, they are recruiting a striker who has scored prolifically in the Portuguese top flight.
The obvious question is how that goalscoring ability translate into the Premier League. If all things go according to plan, we are about to find out.
Arsenal are tired of finishing second, so Gyokeres' task is clear: propel the Gunners to the title