Llanelli held 10-man Gefle to a draw to secure a 2-1 aggregate win and ensure their place in Friday's draw for the Uefa Cup second qualifying round.
The Swedish side struggled from the start and their cause was not helped when defender Thomas Hedlund was sent off for a foul on Jacob Mingorance.
Visiting goalkeeper Mattias Hugosson was in inspired form thwarting Mingorance and winger Craig Williams.
Hugosson also denied Rhys Griffiths and parried a Gary Lloyd free-kick.
Llanelli: Roberts, Lloyd, Neil Thomas, W Thomas, Mingorance, Griffiths, Corbisiero, Belle, Fernandez, Maxwell, Craig Williams.
Subs: Stuart Jones, Appleby, Harrhy,
Jamie Evans, Lewis.
Gefle IF: Hugosson, Hedlund, Patrik Karlsson, Ericsson, Viikmae, Claesson, Bernhardsson, Woxlin, Magnus Wikstrom, Westlin, Makondele.
Subs: Bergqvist, Anders Wikstrom, Hellstrom, Osterberg, Jallow, Ngabu Bapupu, Mattsson.
Referee: A Kulbakov (Belarus)