National Assembly Majority Leader Aden Duale has maintained that he beat Mr Farah Maalim fairly in the August 8 election.
Mr Duale said the votes he got against his rival were far more than what he garnered in 2013, attributing it to "my development record in Garissa Town".
He dismissed reports that he influenced the recruiting of presiding officers and other election officials. He also denied that his sisters bribed voters.
"It is the petitioner who, in fact, provided a list from his clan to be considered for presiding officer positions," he said.
Mr Maalim cited irregularities as the basis for challenging Mr Duale's victory.
"I didn't see the bribery or anyone being bribed but I saw a crowd negotiating," Mr Maalim said.
Mr Duale also rejected reports that the electronic gadgets used in the poll failed on the morning of August 8, adding that the results announced at polling stations were correct.
The MP has also denied making civil servants force Garissa residents to vote for him.
"I did not use violence, threats of force during the election. The allegations are slanderous. No complaint has been made to any police station," the National Assembly Majority Leader said in his affidavit.
The parties concluded giving their evidence and the court directed lawyers to file their submissions before January 11, when they begin their arguments.
Meanwhile, High Court Judge Roseline Wendoh directed the Independent Electoral and Boundaries Commission to give a petitioner challenging the victory of Samburu Governor Moses Lenolkulal access to forms 37A, 37B and 37C.
Former Samburu West MP Simeon Lesirma is challenging Mr Lenolkulal's August 8 win.
The judge also allowed the petitioner a read-only access to data extracted from the Kenya Integrated Election Management System kits.
The court said IEBC, which is the first respondent, should make arrangements for the read-only access to be conducted in the presence of the deputy registrar, political parties and their agents within five days.
However, the court declined two applications by Mr Lesirma.
He had asked the judge to order IEBC to give him full and unfettered access to every biometric electronic appliance used at poll stations.
He had also asked the court to order the commission to provide access to all parties, for scrutiny and supply to the court of original forms 37A, B and C.
Last month, an application by the Samburu County government seeking orders to strike out the petition for failing to enjoin the deputy governor was dismissed by the court.
A plea seeking an order for striking out and expunging from court records respondents' answers for want of service within the statutorily prescribed time was also thrown out.
However, the court allowed an application by Mr Lesirma to file additional supplementary affidavits to support his case.
The case will be mentioned on December 18.
In a related development, former Turkana Senator John Munyes, who is challenging the re-election of Governor Josephat Nanok, now wants a scrutiny of all materials used in the General Election.
Through his lawyer Katwa Kigen, Mr Munyes was given a nod by the court to make an application for the scrutiny to be heard on December 14.
This is after the court completed the hearing of the petition on Tuesday.
Mr Joshua Ang'elei, the lawyer who has teamed up with Mr Kigen, told reporters that the scrutiny would require access to election materials like polling day diaries, ballot papers and Kiems gadgets.
Mr Munyes says the election was marred by malpractices and that Mr Nanok was involved in bribery.