(NewsNation) — After Pennsylvania Senate candidate John Fetterman had difficulty speaking during his highly anticipated debate with Mehmet Oz, the stroke survivor’s campaign blamed the captioning system provided for him as being “delayed” and “filled with errors.”

Nexstar’s communications chief said both candidates were given a chance to test the system twice, but Fetterman chose to only do one rehearsal.

Fetterman is still recovering from a stroke he suffered in May. The debate included closed captioning as an accommodation. Ahead of the debate, both campaigns agreed to have everything the moderators and Oz said typed out on a large screen by captioners providing live transcriptions.

Following the debate aired nationally by NewsNation, Fetterman’s campaign claimed the Pennsylvania lieutenant governor overcame a slow and incorrect captioning system.

“We are thrilled with John’s performance. He did remarkably well tonight – especially when you consider that he’s still recovering from a stroke and was working off of delayed captions filled with errors. John won countless exchanges, counter-punched aggressively, and pushed back on Oz’s cruelty and attacks,” Fetterman for Pennsylvania communications director Joe Calvello said.

“It is unfortunate that Mr. Fetterman is now criticizing the closed captioning process employed by Nexstar during tonight’s debate,” Nexstar communications chief Gary Weitman said in a statement. “Both candidates agreed to the technical set-up for the closed captioning process weeks ago, which was implemented at the request of the Fetterman campaign. Both candidates were offered the opportunity for two full rehearsals with the same equipment used in tonight’s debate; Mr. Fetterman chose to do only one. In fact, Nexstar’s production team went to extraordinary lengths to ensure the effectiveness of the closed captioning process, and to accommodate several last-minute requests of the Fetterman campaign. The closed captioning process functioned as expected during rehearsal and again during tonight’s debate. We regret that Mr. Fetterman and his campaign feel otherwise.”

Nexstar is NewsNation’s parent company.

Fetterman’s performance in the debate has led some political analysts to believe polls may shift more in Oz’s favor in the race to see who will fill the Senate seat currently held by Republican Sen. Pat Toomey.

While providing post-debate analysis on “CUOMO, ” political commentator Chris Stirewalt said he felt while watching the debate it was “irresponsible” for Democrats to encourage Fetterman to proceed in the general election.

“My heart really went out to John Fetterman as he struggled, watching as he tried to answer that question about his flip-flop on fracking was heartbreaking,” Stirewalt said.

On the other hand, Pennsylvania Senator Bob Casey (D) says he thinks Fetterman performed well during the debate and that he does not have any concerns about Fetterman’s health if he would be elected.

“I think tonight we had a lesson in what it means to have a debate about issues even with something as fundamental as closed captioning, which is so basic to our policy over the last 30 years, ever since we had the Americans with Disabilities Act in place. People are doing their jobs every day, working through those challenges like John did tonight. I think he did real well,” Casey said.

As of Monday, Fetterman had a 53% chance of winning the Senate seat over Oz’s 47 percent, according to Decision Desk HQ’s election model.