By Josh O’Brien Liverpool boss Jurgen Klopp has sent Manchester United a stern warning ahead of their meeting with Arsenal next month after their thrilling 2-2 draw on Sunday. Klopp’s Reds made the trip to Old Trafford to take on their fierce rivals knowing a win would be enough to put Liverpool two points clear at the top of the Premier League. Despite taking the lead early on through Luis Diaz, the visitors found themselves trailing with ten minutes to go thanks to two goals from Bruno Fernandes and Kobbie Mainoo. However, a late Mohamed Salah penalty spared Liverpool’s blushes, but was not …