The Astana rider finished ahead of Orica-GreenEDGE's Ewan and Malaysia's Anuar Manan (Terengganu Cycling Team), to take what was also his second victory of the year after winning a stage at the Tour of Oman last month.
Guardini used a strong Orica-GreenEdge train to his advantage, closely marking Ewan before opening up the sprint in the final 200 metres.
(Andrea Guardini won a drag race with Caleb Ewan - LTDL)
I think Orica-GreenEdge have a strong lead-out train, but our team have a good team for working to catch breakaways. So, if we work together in the coming stages, we can expect more wins. - Andrea Guardini
The stage started with a six man breakaway that included eventual mountains classification leader Kiel Reijnen of United Healthcare and Asian riders's classification leader Ma Guangtong (Hengxiang). The group were given little room to play with as an attentive peloton, lead by Orica-GreenEDGE and Astana, kept the gap around just two minutes.
Reijnen was the last rider to be swept up by the chasing peloton with two kilometres to go, setting up the day's expected sprint finish.
Guardini landed the blue jersey for the points classification leader, on top of the yellow jersey as the overall leader after his win.
The 20th edition of LTdL continues with the 180km second stage from Alor Setar to Sungai Petani.
(Caleb Ewan, Andrea Guardini and Anuar Manan - LTDL)
Stage 1: 101km, Langkawi
1 Andrea Guardini (ITA) Astana 02:19:06
2 Caleb Ewan (AUS) Orica-GreenEDGE
3 Anuar Manan (MAL) Terengganu Cycling Team
4 Andrea Dal Col (ITA) Southeast
5 Romain Feillu (FRA) Bretagne - SÃ©chÃ© Environnement
6 Ahmet Orken (TUR) Torku Ã Å¾ekerspor
7 Youcef Reguigui (ALG) MTN - Qhubeka
8 Nikolay Trusov (RUS) Tinkoff - Saxo
9 Francesco Chicchi (ITA) Androni Giocattoli
10 Ken Hanson (USA) UnitedHealthcare
1 Andrea Guardini (ITA) Astana 02:18:56
2 Caleb Ewan (AUS) Orica-GreenEDGE 0:00:04
3 Ma Guangton (CHN) Hengxiang Cycling Team 0:00:05
4 Anuar Manan (MAL) Terengganu Cycling Team 0:00:06
5 Afiq Huznie Othman (MAL) NSC Cycling team 0:00:07
6 Kiel Reijnen (USA) UnitedHealthcare 0:00:09
7 Andrea Dal Col (ITA) Southeast 0:00:10
8 Romain Feillu (FRA) Bretagne - SÃ©chÃ© Environnement
9 Ahmet Orken (TUR) Torku Ã Å¾ekerspor
10 Youcef Reguigui (ALG) MTN - Qhubeka