Defending champion Judd Trump trails 10-6 after the first two sessions of his World Snooker Championship quarter-final ©Getty Images

Judd Trump and Neil Robertson, the top two seeds, are both trailing after the first day of the World Snooker Championship quarter-finals at the Crucible Theatre in Sheffield.

World number one and defending champion Trump trails compatriot Kyren Wilson 10-6 after two sessions, with Wilson, who received a first round bye after his opponent withdrew, three frames away from victory.

After the first four frames of the opening session were shared Wilson won frame five on the final black before winning the next to open up a two frame advantage, which he maintained at the end of session one as he led 5-3.

In the second session, Wilson edged a crucial 12th frame after winning a safety tussle and then potting the final black to make it 7-5 at the mid-session interval.

After Trump reduced the gap to one frame, Wilson won three on the bounce, taking the last of the session with a 63 clearance after Trump missed a red at medium range to lead 10-6 overnight.

Australia's Neil Robertson, the 2010 champion and second seed for this year's event, also needs to overcome a significant deficit as he trails multiple world champion Mark Selby 11-5.

The contest started with the longest frame of the championship which lasted 58 minutes before being clinched by Englishman Selby when he potted the final three colours.

Selby then made two breaks in the sixties and two in the seventies to open up a 5-0 lead before Robertson battled back to claim the last three of the session, which included winning frame eight from 55 points behind, to reduce his arrears to 5-3 at the end of session one.

Second seed Neil Robertson trails 11-5 to Mark Selby after the first two sessions of their World Snooker Championship quarter-final ©Getty Images
Second seed Neil Robertson trails 11-5 to Mark Selby after the first two sessions of their World Snooker Championship quarter-final ©Getty Images

Selby again had the better of a hard-fought second session and threatened to run away with the contest but Robertson won frame 13 on the black to stay in touch, before Selby went on to establish a six frame advantage at the end of the session.

In another match-up between former world champions Wales' Mark Williams, the third seed, opened up a 6-2 lead over England's Ronnie O'Sullivan after the first session of their contest.

The first four frames were shared before Williams pushed on after the interval to take a 4-2 advantage.

O'Sullivan then missed a pink in frame seven and was made to pay by Williams who triumphed in a safety exchange on the colours before taking the last with a break of 130 to lead 6-2.

In the match between two qualifiers Anthony McGill of Scotland and Kurt Maflin of Norway, McGill opened up a 7-1 lead after the first session.

McGill won his first and second round matches in deciding frames, with his last encounter against Jamie Clarke finishing at ten minutes past midnight in the morning on the same day that his match against Maflin started.

McGill raced into a 3-0 lead before Maflin took a scrappy fourth to get himself on the board.

The Scot then extended his lead after the mid-session interval making a break of 92 in the penultimate frame before making a clearance of 81 to open up a 7-1 overnight lead.

All four quarter-finals conclude tomorrow.