Liverpool's Premier League title defence dealt a big blow on Sunday as star defender Virgil van Dijk will undergo surgery on his right knee after damaging ligaments in a challenge by Everton goalkeeper Jordan Pickford during the Merseyside derby. Though the Premier League champions did not give a timescale on Van Dijk's absence, but an injury of that nature is likely to keep the Netherlands international out for a long period with reports that he could miss the rest of the season. Van Dijk was the subject of a reckless lunge by Pickford and the centre-back hobbled gingerly around the field to the changing room.