Football Football Dortmund splashes out on Mainz defender Diallo Abdou Diallo has completed his transfer from Mainz to Borussia Dortmund in a deal that will is said to be worth €28million. Tom Webber 26 June, 2018 19:36 IST Abdou Diallo has become Borussia Dortmund's second-most expensive signing. - Twitter @BVB Tom Webber 26 June, 2018 19:36 IST Abdou Diallo has become Borussia Dortmund's second-most expensive signing after his arrival from Mainz on a five-year contract was confirmed.Dortmund is understood to have shelled out €28million to snare the centre-back, eclipsing its outlay for Henrikh Mkhitaryan but falling short of the €30m spent on Andre Schurrle in 2016.Diallo impressed in his solitary season for Mainz, making 30 appearances in all competitions following his arrival from Monaco for a reported fee of just €5m."After getting to know the Bundesliga at Mainz, I am looking forward to the challenge of being able to prove myself at a club as big as Borussia Dortmund," the 22-year-old said."Together with my team-mates, I want to justify the trust placed in me and do my part to ensure that BVB achieves its goals in all competitions."Now I cannot wait to start preparing for the new season under Lucien Favre." Support Sportstar Dear Reader, Support our journalism — where text and pictures intermingle so seamlessly — and help us scale up your experience as the world changes around us. Your contribution is vital to our brand of uninfluenced, boots-on-the-ground reportage that’s worth your while. Clickbait sensationalism is not for us, but editorial independence is — we owe it to you. Support Quality Journalism Subscribe to our daily newsletter Get your daily dose of Sportstar with handpicked stories delivered right to your inbox! SUBSCRIBE Please enter a valid email address. Dugout videos