Škriniar Manchester United are expected to butt heads with cross-town rivals Manchester City in their pursuit of a new centre-back, as both sides have Napoli's Kalidou Koulibaly and Inter's Milan Škriniar on their wish lists. United are keen to continue their upwards momentum by strengthening in defence, but they will likely have to fend off City, who are desperate to bolster at the back after a hugely disappointing campaign which has seen Pep Guardiola lose more league games than he ever has...