Ms Njoki, who was the personal assistant of Transport Cabinet Secretary James Macharia, started her campaigns in January this year under the slogan "Mrembo na Kazi", which resonated well with a majority of young people in the constituency.
Through that initiative, she sponsored youth sports events, helped some 2,000 young people undertake certificate and diploma courses at different local colleges and organised a food programme that targeted over 50,000 families in a constituency that has 550,000 voters at a time Kenyans are facing harsh economic realities.
And with all that, Ngunjiri had seen his imminent defeat that ended his long political career spanning four decades.
Njoki, who was sponsored by Jubilee Party, won the seat with a total of 34,308 against Ngunjiri's 26,809.
Salat trounced
In another race, Richard Yegon defeated Kanu Secretary General Secretary Nick Salat in the Bomet East parliamentary contest.
Mr Yego, who had in the past 15 years tried his luck in politics, got it right this time around, trouncing Mr Salat and two other candidates.
He clinched the seat after garnering 34,431 votes in a constituency with 63,640 registered voters.
The seat was held by Beatrice Kones, who has retired from politics.
Salat, who made his political debut in 2002 when he defeated the late Kipkalya Kones, has been unsuccessful in his attempts since 2008.
In 2013 and 2017, he unsuccessfully vied for the Bomet senate seat but later switched to Bomet East constituency.
Another parliamentary candidate, who was seen as a political undergo but went ahead to defeat two academicians, is Reuben Kiborek, the Mogotio constituency MP-elect.
Kiborek of UDA defeated Hellen Sambili and the incumbent MP Daniel Tuitoek after he garnered 17,364 voters.
Dr Tuitoek (Independent) emerged second with 13,142 votes with Prof Sambili (Kanu) came third with 1,101 votes.
Stay informed. Subscribe to our newsletter
Kiborek first vied for the seat in 2017 under Jubilee Party but was defeated by the outgoing MP in party primaries.
In April, during UDA party primaries, Kiborek emerged second but protested the results, citing irregularities.
The father of one told The Saturday Standard in a phone interview that his journey started in 2007 while at Baringo High School where he and other students formed Mogotio parliamentary committee meant for the 2017 elections. He said they had felt as a union that it was time for the youth to be accorded time to be leaders.
"I believe God has a purpose for my victory. I started this journey in 2007 while at Baringo High School as a Form One student. We formed a committee, which had an agenda of campaigning in 2017 for the MP seat," Kiborek said.
Kiborek's popularity was witnessed a week before the elections when the UDA party leader Deputy President William Ruto made an unscheduled trip to Mogotio while touring Baringo County where he campaigned for him.
Tuitoek holds a PhD in Water Resources Engineering from the University of Alberta in Canada and was a senior lecturer at the department of Civil Engineering at Egerton University before being elected MP in 2017.
Re-elected but lost
Sambili, on her part, holds a PhD in Education from Lancaster University. She won the seat in 2007 on an ODM ticket and was re-elected in 2013 but lost the seat to Tuitoek in 2017.
Sambili was appointed Garissa University Chancellor in 2017 after losing her parliamentary seat.
For 31-year-old little-known John Methu, the path to clinching the Nyandarua senate seat was like a dream.
Mr Methu beat all the odds to defeat a political veteran who was once a minister and senator, Mwangi Githiomi, and lawyer Kinyanjui Theuri.
From the little-known Karoboithi village, Njambini Kiburu Ward in the vast Kinangop constituency, Methu beat all the odds - from walking on foot to riding on a bicycle during campaigns - to emerge the winner.
Methu, a Bachelor of Arts degree in Political Science and Sociology holder, describes himself as an ambitious young man.
"I always believe in myself. This time around, God has answered my prayers and I believe that I will work hard so that Nyandarua can develop," he said.
In 2017, at the age of 26, he contested for the same seat but lost to Githiomi.
Methu, popularly known as "The Black Senator" won in four out of the five constituencies.
"This, I thought, could work better for me as I could visit people in their homes. Every day, for the last five months, I would have a programme on which village to visit, even on foot. Residents welcomed me and offered me food," he said.
Before he contested for the seat, he worked as the personal assistant to the Nyandarua County Assembly speaker Ndegwa Wahome.
[Ben Ahenda, James Munyeki, Gilbert Kimutai and Yvonne Chepkwony]