Lighthizer's optimism comes about a year after renegotiations began following Trump's threat to exit the free trade pact with Mexico and Canada because it was a "disaster" and an unfair deal to American workers.
After long and hard negotiations among the parties to the North American Free Trade Agreement - all against the backdrop of President Donald Trump's well-known opposition - a breakthrough may be at hand. The Trump administration has said an agreement with Mexico will put pressure on Canada to soften some of its demands.
Some areas related to auto rules of origin remain unresolved, including the time frame to implement changes in the new rules, while a "sunset clause" that could kill NAFTA after five years has not yet been discussed, Guajardo said.
"Their tariffs are too high, their barriers are too strong, so we're not even talking to them right now".
NAFTA talks ground to a halt in late May in the run-up to the presidential election in Mexico on July 1. We want to make the right deal.
Recent discussions with Mexico are largely over provisions affecting the auto industry, and Guajardo said the sides had made "a lot of progress", but still needed to finalize details like the transition period for implementing new commitments.
"Hopefully we will be able to close up no later than the middle of the week the remaining issues and probably there will be space to start the trilateral", Guajardo said a day after the one-year anniversary of the talks' start. "I'm hopeful with Mexico".
After the election, USA and Mexican officials began meeting again without the third member of the pact, Canada, in an effort to tackle hard issues, including revamped automotive sector rules and a sunset clause that could kill NAFTA after five years if it is not renegotiated.
U.S. President Donald Trump is suggesting Canada has deliberately been left on NAFTA's sidelines as one-on-one talks heat up between Washington and Mexico.
Guajardo has stressed that the most hard issues had been left to the end, including the USA demand that NAFTA be approved every five years, a provision known as a sunset clause. He says a number of individual issues have plagued negotiators for the past few months.