Top 5 transfers in Europe: Martinez, Mandzukic, Imbula, Kondogbia, Castro
If there's one thing we can be sure of in this summer's transfer window, it's that the Premier League will continue to be the epicentre of big business. The recent transfer of Dimitri Payet from Marseille to West Ham, for example, showed how uneven the playing field is, with a star leaving one of Europe's biggest traditional names for a reported salary of £65,000-a-week that the French giants couldn't dream of paying.
Yet there's plenty going on elsewhere in Europe. Italy is the biggest spender of the top five European leagues so far with new investment in Milan meaning Serie A spend is likely to climb further. With many Spanish and Portuguese clubs attempting to find a way around FIFA's ruling against third-party ownership, these are continental Europe's most eye-catching deals of this summer to date.
Jackson Martinez - FC Porto to Atletico Madrid - €35 million
Since arriving in Portugal from Mexican club Chiapas FC in 2012, the imposing Colombian striker has been continually linked with a move away. After an impressive 92 goals in 132 matches for Porto, that speculation has finally come true, as it has been confirmed that he will play for Atletico next season (the first of a four-year deal).
If there's no such thing as a €35 million bargain, the 28-year-old isn't far short of it. He's at his absolute peak, able to play with his back to goal yet happy on the front foot too. As impressive as the volume of goals that Jackson scores is, it is the variety of goals he scores -- headers, flicks, side-foots and drives -- which underline his ability to think on his feet.
Mario Mandzukic - Atletico Madrid to Juventus F.C. - €19 million
The decks were cleared for Jackson's arrival at the Vicente Calderon by the sale of Mandzukic to the Champions League finalists, who are themselves in need of experienced forward reinforcement after the return of Carlos Tevez to Boca Juniors. The Croatian is not, of course, a direct replacement for Tevez, with the €40m arrival of Paulo Dybala from Palermo covering that brief.
The pedigree of Mandzukic is in no doubt. His goal ratio in elite teams -- FC Bayern Munich and Atletico -- over the last two seasons is excellent, and his strength and tactical intelligence means he'll fit into Juve's powerful, exacting approach.
The only concern is how he'll react to further rotation. Both Pep Guardiola and Diego Simeone felt Mandzukic showed total commitment when he was playing, but was prone to sulking when not in the XI. Can he really expect to play every game in Turin? Much depends on whether he can form a workable partnership with rising star Alvaro Morata.
Giannelli Imbula - Marseille to FC Porto - €23 million
Both Milan clubs, Valencia, Southampton and West Ham were all heavily linked, but Porto will land Imbala, one of Europe's most promising defensive midfielders, in the most surprising big-money deal of the summer so far. Marseille are reported to be banking up to €23m (a Porto record), while the 22-year-old is set to become the highest-paid player in the Dragons' history.
The deal is far from straightforward. Reports have suggested that Doyen Sports have contributed almost half of the fee -- it's hard to imagine Porto being able to shell out that sort of money without aid -- though with new third-party ownership deals outlawed, the insistence is that Porto's holding company will retain 100 percent of Imbula's economic rights.
It's an unlikely marriage between player and club, but there are strong advantages on either side. Imbula gets to compete in the Champions League with a perennially strong side, and to use the club as a stepping stone to another challenge (which wouldn't have been possible with Inter, a move he never really fancied), in 12 months' time if all goes well. Porto get to develop a player of extraordinary natural gifts, display him in the biggest shop window and hopefully, sell him onto a Premier League giant at a big profit.
Geoffrey Kondogbia - AS Monaco FC to Inter Milan - €35 million
It's sometimes hard to believe that Kondogbia is only 22, with his move to San Siro taking him to a third major league already. The good news for Inter, and for those fans baulking at a €35m fee, is that he has already been highly successful outside France, excelling in his sole season at Sevilla FC after arriving as a teenager and attracting the lingering attention of Real Madrid FC.
Comparisons are often made with Giannelli Imbula, given the pair are both young, athletic (and left-footed) central midfielders, but their core attributes diverge; Imbula is a skilled dribbler, while Kondogbia relies more on power. Roberto Mancini's new man could do with becoming a little more two-footed, if truth be told; his total reliance on his left has implications in terms of bringing the ball out from in front of the defence.
Kondogbia has, however, already shown great character in overcoming a tough start at Monaco, and in living with a weighty price tag after the Principality club paid €20m for him in a hostile buyout in 2013. His fine performances in the Champions League -- notably against Arsenal F.C. -- give hope that he is a man that Mancini can build his new side around.
Gonzalo Castro - Bayer Leverkusen to Borussia Dortmund - €11 million
We're told that the Thomas Tuchel reign will be about evolution, not revolution, but the tired copy of Jurgen Klopp's best side that finished last season desperately needed new blood.
Enter Castro, brought in from Bayer Leverkusen the day after the season's end for the full €11 million stipulated in his buyout clause. There is, in fact, something quite Bayern-esque about this transfer, with Die Schwarzgelben strengthening while simultaneously weakening a Champions League rival.
Nevertheless, Castro is a great signing, full of energy and enterprise, versatile and experienced both in Bundesliga and European competition. The pity for Tuchel is that he wasn't able to pair the new man with his old Mainz muse Johannes Geis, as the difficulty in shifting Ilkay Gundogan -- which looks like resulting in the Germany midfielder staying at Oberliga Westfalen -- meant Geis joined local rivals Schalke instead. We will have to wait and see if Tuchel has cause to regret it.
Andy Brassell is a writer/broadcaster/producer for BBC, Guardian, Mirror, Talksport, BT Sport, WhoScored. Follow him on Twitter @andybrassell.