Partey joined the Gunners from Atlético Madrid after they triggered his £45 million release clause.
Ex-Arsenal star, Paul Merson, has named Thomas Partey as the “number one” signing made by any Premier League club over the summer.
The Ghanaian impressed on his debut – a 2-1 Europa League win over Rapid Vienna and produced an excellent midfield display as they beat Manchester United in his second Premier League start.
While Merson refused to get carried away by the victory at Old Trafford, he heaped praise on Partey for his “massive” display.
“They beat a terribly, terribly poor Manchester United team on the day. They’ve done a job, we’ve seen them lose those games over the last five or six years.
“But I think Partey’s a massive, massive difference. I mean, what a signing.
“When you talk about signings in the summer, he’s got to be number one. I cannot believe, without being horrible here, that Arsenal got him,” Merson said on Sky Sports.