El Clasico, the Manchester derby and the meeting of Serie A's top two are among the highlights of the International Champions Cup calendar in North America.

Paris Saint-Germain and Tottenham join Real Madrid, Barcelona, Manchester United, Manchester City, Juventus and Roma in the United States for the glamourous pre-season tournament.

Roma and holders PSG kick off the event in Detroit on Wednesday, with neither side having enjoyed an encouraging few weeks in the transfer window.

For all the talk of spectacular swoops for Neymar, Philippe Coutinho and Alexis Sanchez, the arrivals of full-backs Dani Alves and Yuri Berchiche have been the extent of PSG's signings.

The appointment of Antero Henrique as sporting director in June was expected to herald a drive in the market, and although there are some weeks left until the window closes, PSG look no stronger than they did at the end of last season, when they surrendered the Ligue 1 title to Monaco.

It's even worse for Roma, though. Monchi's arrival as sporting director has yielded a number of additions but an exodus of top talent, despite him having insisted the club "is not a supermarket" some weeks ago.

Maxime Gonalons, Rick Karsdorp, Hector Moreno, Cengiz Under and Lorenzo Pellegrini are among the acquisitions but the sales of Mohamed Salah, Antonio Rudiger and Leandro Paredes have left fans angry. Many fear another year of playing second-fiddle to Juve, whose squad remains strong and perhaps a little more harmonious in the wake of Leonardo Bonucci's shock AC Milan move.

Manchester City have likewise endured something of a frustrating window. The swoop for Bernardo Silva at the end of the season was a masterstroke but Pep Guardiola's plans have hit roadblocks at almost every other turn - missing out on Alves to PSG is said to have rankled in particular.

Big money has been spent on Ederson and Kyle Walker, now officially the most expensive English player in history, and his inclusion will certainly make City's clash with Spurs in Nashville on July 29 a spicy affair.

Before that, though, is the small matter of the Manchester derby in Houston. Jose Mourinho's side have performed well in friendlies against Real Salt Lake and LA Galaxy and there is undeniable excitement around United's open training sessions now that £75m man Romelu Lukaku is in tow and off the mark.

While Mourinho against Guardiola is rarely a moment to be missed – and fans will be especially keen on this one after their meeting in China a year ago was cancelled because of a poor pitch – it is the Portuguese facing off against old club Real Madrid that will set most tongues wagging.

The Spanish and European champions meet United in Santa Clara on July 23 in what will be Mourinho's first encounter with his former employers since he left in acrimonious fashion in 2013.

Madrid have bigger concerns than any lingering bad blood, of course, with the future of Cristiano Ronaldo still the subject of much debate. The ICC will give Madrid fans a glimpse of what life could be like without the Portugal star, given he has been granted extended holiday after the Confederations Cup and will not be taking part.

The highlight of the tournament will almost undoubtedly be the Clasico, though. Ernesto Valverde will get his first taste of facing Madrid as Barcelona boss in Miami on July 29, at the end of a week in which they face both United and Champions League runners-up Juventus.

Gerard Deulofeu and Rafinha will miss out on the US trip but Nelson Semedo, a €30m signing from Benfica, could be involved. Lionel Messi, Luis Suarez and Neymar are all expected to feature, giving fans a chance to watch the former for the first time since he signed a new contract that reportedly made him the world's best-paid player.

Messi scored a last-second winner when these sides last met at the Bernabeu in LaLiga and this game is unlikely to be played as a mere pre-season warm-up. The ICC trophy will not matter much come the end of 2017-18, but the confidence boost of a Clasico win as early as July should not be underestimated.