Playing his first match since a semi-final loss to Tim Henman last month in Paris, where he took possession of the top ranking, Roddick had looked poised for a routine return to competition but in the end needed a tense one hour and 35 minutes to secure his first Masters win.
The victory ends Wimbledon champion Roger Federer's hopes of finishing the season in top spot, the battle for number one now down to a two-way fight between Roddick and French Open champion Juan Carlos Ferrero of Spain.
"It's just a relief, good to get the first one ... get through the first one with a win," Roddick said.
"It keeps it from being an uphill battle, especially with the race for number one being so close."
"Every match win is very big."
Having spent the last week in New York rehearsing to host "Saturday Night Live", Roddick was back on a more familiar stage and showed no signs of rust as he stormed through the first set to the delight of pop star girlfriend Mandy Moore who applauded her approval from the front row.
Any thoughts Roddick had of a quick evening, however, disappeared along with U.S. Open champion's composure in the second set.
Serving at 0-1, Roddick flew into a red-faced rage on a disputed line call, losing his concentration and control of the match as Moya went on to break the 22-year-old American and jump back into the contest.
Agitated, Roddick continued to be distracted by the call, swearing repeatedly and arguing with chair umpire Mike Morrissey during the changeover, as the veteran Spaniard seized his opportunity levelling the match at one-set all.
"It affected me the next game," admitted Roddick.
"I try to let it go pretty quickly."
"I probably should have kept it together a little bit more and not hit an angry double-fault."
"But luckily I was able to recover in time for the third set."
REGAIN COMMAND
Struggling to regain command of his churning emotions and the match, Roddick finally wrestled back control of the contest late in the third set breaking Moya to go up 5-3, then holding serve to clinch the win.
Other than losing his temper, Roddick produced a solid effort in his first match on American soil since his U.S. Open triumph, thundering 14 aces past the seventh-ranked Spaniard.
Texas has provided a happy hunting ground for Roddick, who claimed what was then his second career title last year in Houston while advancing to the final of this year's event, making him the fan favourite at this $3.65 million season finale.
Earlier in the day in other Red Group action, Germany's Rainer Schuettler survived an uneven performance on what he claims is an uneven court beating Guillermo Coria 6-3, 4-6, 6-2.
Critical of what he labelled a slanted stadium court, Schuettler and his Argentine opponent both struggled to find their rhythm during the roller-coaster two hour, 25 minute match.
The Blue Group will take centre stage on Wednesday as round-robin play continues with Switzerland's Federer taking on Argentine David Nalbandian and Andre Agassi facing Ferrero in a rematch of their U.S. Open semi-final.
