SINGAPORE - Emeritus Senior Minister Goh Chok Tong has congratulated Malaysia's Mahathir Mohamad on becoming his country's prime minister for a second time, adding that the 92-year-old has scored a "stunning victory" with his coalition partners.

Mr Goh posted his Facebook message on Thursday evening (May 10), a day after Dr Mahathir's opposition coalition Pakatan Harapan won Malaysia's 14th general election - against the prediction of many analysts.

Drawing parallels between Dr Mahathir and Singapore's late founding prime minister Lee Kuan Yew, Mr Goh wrote: "Watching Mahathir fight Malaysian GE14 reminds me of Lee Kuan Yew who famously said, 'Even from my sick bed, even if you are going to lower me into the grave and I feel something is going wrong, I will get up.'"

The memorable quote was uttered during Mr Lee's National Day Rally speech in 1988, when he was preparing to hand over the premiership to Mr Goh.

Dr Mahathir has said that his decision to return to politics in his 90s was motivated by Prime Minister Najib Razak's rule, which was embroiled in a corruption scandal involving state-owned company 1MDB.

Mr Goh, 76, said: "One must salute Mahathir for his indomitable will and energy to right what he thinks is wrong with his country. He and his coalition partners scored a stunning victory."

Mr Goh's tenure as prime minister - from 1990 to 2004 - overlapped with Dr Mahathir's, which lasted from 1981 to 2003. The two prime ministers cooperated on many issues, but also had notable disagreements, including a series of tense exchanges over the price of water between 1998 and 2003.

On Thursday, one elder statesman had words of good wishes for the other.

"Congratulations to them on their success, and to Mahathir on becoming the Prime Minister of Malaysia for the second time.

"Whatever happens on one side of the Causeway affects the other. This is a historic and unprecedented moment for our closest neighbour. We wish them well and success, and offer Mahathir and the new government our continued goodwill and friendship."

Pakatan Harapan's victory marks Malaysia's first transition of power since independence, after 61 years of rule by coalitions led by the United Malays National Organisation (Umno).

Dr Mahathir is due to be sworn in as Prime Minister on Thursday night.