He first started playing Defense of the Ancients before moving onto League of Legends because he felt the game emphasized on teamwork more than any other action RTS games out there and was thus, much more interesting and challenging.
Westdoor was most known very well as a prominent solo queue player, ranking very highly on NA before the establishment of a Taiwanese server. He created a reputation for himself as an immaculate Twisted Fate player. westdoor soon would join with the amateur team, Tt Dragons, where he would dominate small domestic tournaments. His team even placed 3rd at IPL 5 Taiwanese qualifiers. It however, did not take long for Westdoor to look towards more than an amateur team. Westdoor had a contract issue with the team and was suspended for six months from competitive play. He would become a very well known streamer around this time, often streaming from net cafes. Eventually ahq e-Sports Club inquired about Westdoor and would sign him to replace Artie in May of 2013.
Westdoor in his first professional season with ahq was very strong, being an important part of their 2013 GPL Summer run, taking first with the right to challenge the reigning world champions, and 2013 GPL Spring winners, Taipei Assassins. Ahq came in the favorite and defeated the Assassins 2-0 to win the split and end the TPA stranglehold over the region. This was the beginning of Westdoor's and Lantyr's popularity among the Taiwanese fans. Unfortunately, they would not qualify for worlds losing to the Gamania Bears.
Ahq would falter as a top contending team within the region often being beat out by the Taipei Assassins over the course of the season. Westdoor and club however would be able to clinch a berth for the 2014 Season World Championship after placing second in the SEA regionals. Westdoor would play a very important part in their upset win over Edward Gaming, the number one seed in China, to force a tiebreaker. Ahq however lost the game to EDG in front of their home crowd, being eliminated from the tournament.
Placed directly into the finals of the gauntlet-style playoffs, they once again won the season, this time beating Hong Kong Esports 3-0 and automatically qualifying for the 2015 Season World Championship.
At Worlds, ahq were seeded into Group B, along with Fnatic, Invictus Gaming, and Cloud9 and went 3-3, advancing to the playoffs after a tiebreaker victory over Cloud9 (giving the North American team their fourth loss in a row that day). Their World Championship run ended in the quarterfinals, where they were drawn against tournament favorites SK Telecom, earning a top 8 finish.
Although the handle "SimonNight" is listed on Tt Dragon's English website, Liu has never actually used that name in any tournament games so far. He has an account on the North American server with the IGN "westdoor0204", a handle which he uses occasionally in competitions. As Tt Dragons has yet to play in any major tournaments on the English tournament servers, we do not yet know what is his preferred English IGN. Both "SimonNight" and "westdoor" are possible approximated transliterations of his Taiwanese IGN "西門夜說".
He was once ranked number 1 in the North America, Taiwan and number 2 in the Korea solo queue ladder.