Aaron Ramsey warned Juventus needs to be wary of the threat posed by his former Arsenal team-mate Alexis Sanchez when the Italian champion faces Inter on Sunday.
Sanchez played alongside Ramsey for three-and-a-half seasons at Arsenal, where the pair enjoyed two FA Cup triumphs together, but they go head-to-head in a top-of-the-table-clash at San Siro.
Since joining Inter on loan from Manchester United in August, Sanchez has made three Serie A appearances and opened his goal-scoring account for the club in a 3-1 victory at Sampdoria.
Ramsey scored his first goal since his move from Arsenal to Juventus a week earlier, netting the Bianconeri's equaliser in a 2-1 win over Verona, and he said his side are braced for a tough challenge against the league leader this weekend.
"Inter have improved this season," Ramsey told BBC Sport .
"Antonio Conte has got them really organised and they have yet to drop any points. It is going to be difficult.
"They have some great players, including one I know very well from my time at Arsenal. We will have to be aware of him and the other players they have and be really on top of our game to get the result we want."
Juventus has only dropped two points in Serie A this season but that leaves it trailing Inter who has won all six of its games under new coach Antonio Conte.
Ramsey indicated that he feels Juve will improve as it adapts to the methods and tactics being used by coach Maurizio Sarri, who took charge in June.
"It has been great so far," said Ramsey when asked about working under the former Chelsea coach.
"There have been new ideas and new information, which we are working hard to try to put into practice. At times it hasn't worked as well as we would have liked, but in other parts it really has.
"We are slowly getting better in terms of what he wants to implement and understanding our roles and responsibilities more.
"This club has been so good and so dominant for so long. We know other teams have improved and are trying to knock us off top spot. But this place is all about winning and that is what we are striving for."