Recent polls have shown both candidates are neck and neck in their popularity ahead of the November election, and a good performance this week could set the tone for either candidate for rest of the debates.
The election has yet to affect markets in a major way - but traders and investors are beginning to pay closer attention.
On Friday, a Reuters report suggested Saudi Arabia had reportedly agreed to trim its production on the condition that Iran capped its own output. The report sent oil prices climbing, before a second report, quoting an unnamed Saudi official warning the market to not expect a deal, resulted in a pullback.
Beyond this week, markets would be keeping an eye on the U.S. non-farm payrolls report for September due next Friday.
It would be the first of several key data points between now and the Fed's December meeting that could offer clues on the timing of the next interest rate hike.
In this week's Trader Poll, tell us what is affecting your trading strategy?