The Swede has encouraged his rival to be prepared for the Manchester derby.
Lionel Messi is currently undergoing physiotherapy in Barcelona after returning from international duty.
The German boss moved to Anfield in 2015.
The record-breaking forward is Barcelona's all-time top goalscorer.
The 22-year-old moved to the Etihad Stadium earlier this summer.
Lionel Messi returned to international duty against Uruguay after announcing retirement post Copa loss.
Jack Wilshere will be allowed to leave Arsenal on loan on transfer deadline day.
Luan played a key role in helping Brazil win their first football gold at the 2016 Olympic Games.
Nottingham Forest winger Oliver Burke, 19, is also attracting interest from Bayern Munich.
Catalan giants looking to continue perfect start to season at San Mames.
The Chile international signs a four-year deal at the Etihad Stadium.
The Champions League draw will take place at 5pm BST on 25 August, Thursday.
Pique says he will fondly follow Manchester City this season.
Neymar and his former girlfriend Carolina Nogueira Dantas share custody of their son.
England international is not on Anfield club's radar at present, according to reports.
Gabriel Barbosa was part of Brazil's gold medal winning Olympic football team at Rio 2016.
Barcelona will be without injured skipper Andres Iniesta for their opening game against Real Betis.
Riyad Mahrez has been on Arsene Wenger's radar this summer.
Sevilla face a mountainous task against Barcelona in the second leg of the Spanish Super Cup.
Calleri was part of Argentina's squad that was knocked out in the group stages of the Rio 2016 Olympics.
Luis Enrique's side begin season in earnest with Spanish Super Cup first leg clash against Sevilla.
Juanma has been on trial with Liverpool since the end of July after being released by Barcelona.