Only five of the scheduled men’s singles were able to be completed before play was halted at SW19 by the rain.
Following heavy downpours, the referee’s office finally called play off shortly after 7.45pm, leaving a considerable backlog of matches.
Roddick, who did not get out on Centre Court himself for the original 1pm start because of continued drizzle, rattled through the opening exchanges against Danai Udomchoke of Thailand.
The number three seed, who won the Artois Championships at Queen’s, found himself in command at two sets to love up in just over 50 minutes.
However, Roddick — twice a beaten finalist at Wimbledon — was pushed hard by the world number 114 in the third set. Eventually, though, the American’s experience saw him through 6-3 6-4 7-6 (7-3) after the best part of a two-hour workout.
“I am not a finished product but, I am, getting there.
“You are always looking to improve,” said Roddick.
The American will face Fernando Verdasco for a place in the last 16 following the Spaniard’s straight-sets win over Andreas Seppi.
Elsewhere, defending champion Roger Federer, the top seed, was leading Argentina’s Juan Martin Del Potro 6-2 7-5 and 2-0 in the third set on Court One.
Federer was on the verge of his 50th straight victory on grass before the Wimbledon weather intervened.
Another seed to make it through before the rain came was Fernando Gonzalez.
The Chilean, seeded fifth, needed four sets to get past Alejandro Falla, of Columbia, 4-6 6-3 6-4 7-6 (7-1).
He will face Serbian Janko Tipsarevic, who knocked out Florent Serra after a five-set marathon.
Richard Gasquet, the 12th seed, beat fellow Frenchman Nicolas Mahut 6-4 6-3 6-4.
“I feel good on grass,” he said.
British number two Tim Henman was level at 1-1 in the first set with Feliciano Lopez on Centre Court when the rain intervened.
Number 13 seed Tommy Haas, of Germany, was ahead against Czech player Tomas Zib by one set to love on Court 18.