Arsenal appeared to make a breakthrough in their pursuit of a striker on Sunday when it was reported that they had advanced talks with Sporting CP's Viktor Gyokeres.
The Gunners have been keen to strengthen in the final third after finishing without silverware once again last season and identified Gyokeres, 27, and RB Leipzig striker Benjamin Sesko as two of their top targets.
A potential deal for Gyokeres - which would see him swap Lisbon for London - could be worth up to £70million.
Talks have taken place over the structure of achievable bonus payments on the fee with Gyokeres having already agreed personal terms on a five year contract.