After Ana Ivanovic's exit, Kirilenko is the highest-ranked player in the draw and she prevailed 7-6 6-3 after a 130-minute battle with fellow Rusian Elena Vesnina.
The world number 15 will now meet fourth seed Sorana Cirstea who swept past Anastasija Sevastova of Latvia – the world number 183 – 6-3 6-0 inside an hour.
Former Wimbledon semi-finalist Sabine Lisicki had to work considerably harder for her place in the last four, however, as she recovered from a set down to beat Marina Erakovic of New Zealand 5-7 6-3 6-2 in 138 minutes.
Ayumi Morita of Japan arrived in Thailand high on confidence after a third round run at the Australian Open but after beating both Ivanovic and Kimiko Date-Krumm at the rain-hit tournament on Thursday, fatigue took hold and she went down in three sets to Nina Bratchikova.
WTA Pattaya results
2-Maria Kirilenko (Russia) beat 7-Elena Vesnina (Russia) 7-6(6) 6-3
4-Sorana Cirstea (Romania) beat Anastasija Sevastova (Latvia) 6-3 6-0
5-Sabine Lisicki (Germany) beat Marina Erakovic (New Zealand) 5-7 6-3 6-2
Nina Bratchikova (Russia) beat Ayumi Morita (Japan) 6-1 3-6 6-1