Former champion Gerwyn Price began his bid to regain the world darts title with a 3-0 win over Keane Barry, while there was an emotional defeat for Cameron Menzies.
Welshman Price, who won the PDC World Championship in 2021, averaged 91.31 as his Irish opponent missed 22 doubles in the second round.
Scot Menzies struggled to keep his emotions in check as he fell to a 3-1 defeat against American world number 130 Leonard Gates.
Menzies, ranked 39th, looked distraught as the game progressed and wiped away tears in the latter stages of his first-round loss.
Price has endured a largely frustrating 2024 but said he was playing some of his best darts going into this year's world championship.
The 10th seed is scheduled to face Joe Cullen in the third round, should his compatriot overcome the winner of Wessel Nijman and Cameron Carolissen.
Four-time semi-finalist James Wade was earlier knocked out in the second round by Jermaine Wattimena, while England's Connor Scutt averaged nearly 102 in an impressive 3-0 win over Ben Robb.
Wade was the first seed to exit this year's tournament after being overpowered by by Wattimena.
Wade, a former Premier League, World Matchplay and World Grand Prix champion, lost 3-0 in the final match of Monday's afternoon session.
Englishman Wade, a four-time semi-finalist, received a bye to round two as the 16th seed.
Wattimena, 36, will face either two-time world champion Peter Wright or Wesley Plaisier in the third round.
The Dutchman was the first player to have played on both days of this year's World Championship after beating Swiss debutant Stefan Bellmont 3-0 on Sunday.
Having lost the opening leg to Wade, Wattimena reeled off eight straight legs to win the first two sets and move within one leg of a second-round victory.
Wade hit double 20 to avoid a whitewash in the final set, but Wattimena took advantage of Wade's missed doubles to seal the win.
Wattimena averaged 99.17 in the match, with Wade on 97.01.
Afternoon - First round
Wesley Plaisier 3-2 Ryusei Azemoto
Luke Woodhouse 3-0 Lourence Ilagan
Alan Soutar 1-3 Kai Gotthardt
Second round
James Wade 0-3 Jermaine Wattimena
Evening - First round
Niels Zonneveld 1-3 Robert Owen
Connor Scutt 3-0 Ben Robb
Cameron Menzies 1-3 Leonard Gates
Second round
Gerwyn Price 3-0 Keane Barry