U.S. stock index futures erased losses to trade positive as the debate kicked off. Futures were near session highs as the debate ended, with Dow futures briefly adding more than 100 points.

"Early indications suggest Hillary won the debate; at least didn't lose. Futures are higher and the peso is rallying," said Jack Ablin, chief investment officer at BMO Private Bank.

Hillary Clinton appears to have edged out her Republican opponent Donald Trump in the first presidential debate, based on analysts' take on the market reaction.

In the last few days, the Mexican peso has hit all-time lows against the U.S. dollar as Trump appeared to gain momentum in election polls.

The U.S. dollar last traded about 1.8 percent weaker against the Mexican peso and was stronger against the yen. The euro-dollar held steady near $1.125.

The Dow Jones industrial average closed more than 150 points lower Monday, weighed by concerns ahead of the evening debate and pressure on the financial sector from a plunge in shares of Deutsche Bank to record lows.

"I think Hillary Clinton did pretty well. I think she was better prepared than Trump," said Bruce Bittles, chief investment strategist at Baird. "Whether the debate will mean anything (remains) to be seen."



Key market issues such as drug pricing and breaking up the banks were not discussed at this debate. But both candidates agreed on the need to strengthen cybersecurity. Clinton focused more on combating terrorism in cyberspace, while Trump said hacking and cyberwarfare was a "huge problem."



Paul Christopher, head global market strategist at Wells Fargo Investment Institute, said Clinton's "direct references to supporting Arab allies against ISIS was also a strong statement that reiterated the current administration's approach, although she did not offer much that was new."

"Mr. Trump agreed that we could be better at cybersecurity, but his answers were diffuse and unfocused, and handicapped by his well-known favorable comments about Russian President [Vladimir] Putin," Christopher said. "Mr. Trump could have said more about opening a broader cyber front against ISIS."

To be sure, the immediate Monday night market reaction to the debate could reverse, and analysts were quick to point out that there are still two more presidential debates to come ahead of the November election.

"If markets think she did well, then the polls need to reflect that. In the financial industry, the (market participants), they can have an assessment she won. That doesn't mean the average voter has the same view," said Andres Jaime, global FX and rates strategist at Barclays.

"If a poll in the next few days shows the race is as tight as it (was heading into the debate), then markets will probably sell off," he said. He said clarity on the latest polls should come by the end of the week.