The popular American had the crowd dancing to his tune during a highly entertaining walk-on and they were soon off their feet again during an explosive first set which he won 3-0 thanks to checkouts of 138, 120 and 85 on the bullseye.
A shell-shocked Menzies showed some character to bounce back and pinch the second set 3-2 but his struggles promptly returned as the pressure of the big staged seemed to get to him while the crowd heavily favoured his opponent.
But as Gates enjoyed one of the biggest victories of his life to set up a second-round meeting with Nathan Aspinall, Menzies was having to fight away the tears during the fourth set which he lost 3-2.
Elsewhere on Monday night, a fired-up Gerwyn Price roared into the third round with a 3-0 victory over Keane Barry.
The Iceman wasn’t at his best with an average of 91.32 but played well enough to punish the young Irishman for missing 22 of his 24 darts at a double.
During the afternoon session, James Wade became the first seed to exit the competition when an inspired Jermaine Wattimena brushed him aside 3-0.
The in-form Dutchman averaged 99.17 compared to Wade’s 97.01 but the key difference between the pair was on the doubles, with Wattimena pinning 50% of his 18 attempts while his opponent spurned 14 of his 16.
The defeat meant the Machine crashed out at his first hurdle for the third year in a row.
England’s Luke Woodhouse enjoyed a 3-0 victory over Lourence Ilagan in the first round, although he was booed for turning down a chance at the highest possible checkout.
Woodhouse, who won the first seven legs in succession before Ilagan finally got off the mark with a 103 finish, needed 170 to complete victory and hit successive treble 20s, but refused to go for the bull.
The crowd made their feelings known but Woodhouse had the last laugh as he took out 32 on his next visit to seal a comfortable victory.
Germany’s Kai Gotthardt overcame a broken dart as he marked his tournament debut with a 3-1 win over Scotland’s Alan Soutar.
The barrel of one of Gotthardt’s darts snapped in half during the fourth leg of the first set, won by Soutar, but Gotthardt stormed back to take the next three sets in succession.
In the first match of the day, Holland’s Wesley Plaisier recovered from 2-1 down to beat Japan’s Ryusei Azemoto 3-2 and set up a second-round meeting with former champion Peter Wright.
Day two results and day three schedule
Monday December 16
Afternoon Session (12.30pm GMT)
First/Second Round (Best of 5 sets)
TV Coverage: Sky Sports Darts
- Wesley Plaisier 3-2 Ryusei Azemoto (R1)
- Luke Woodhouse 3-0 Lawrence Ilagan (R1)
- Alan Soutar 1-3 Kai Gotthardt (R1)
- James Wade 0-3 Jermaine Wattimena (R2)
Evening Session (7pm GMT)
First/Second Round (Best of 5 sets)
TV Coverage: Sky Sports Darts
- Niels Zonneveld 1-3 Robert Owen (R1)
- Connor Scutt 3-0 Ben Robb (R1)
- Cameron Menzies 1-3 Leonard Gates (R1)
- Gerwyn Price 3-0 Keane Barry (R2)
Tuesday December 17
Afternoon Session (1230pm GMT)
First/Second Round (Best of 5 sets)
TV Coverage: Sky Sports Darts
- James Hurrell v Jim Long (R1)
- Kevin Doets v Noa-Lynn van Leuven (R1)
- Ryan Joyce v Darius Labanauskas (R1)
- Mike De Decker v Woodhouse/Ilagan (R2)
Evening Session (7pm GMT)
First/Second Round (Best of 5 sets)
TV Coverage: Sky Sports Darts
- Jeffrey de Graaf v Rashad Sweeting (R1)
- Ricardo Pietreczko v Xiaochen Zong (R1)
- Ryan Meikle v Fallon Sherrock (R1)
- Peter Wright v Plaisier/Azemoto (R2)
