He and his teammates celebrated anyway.
"It feels great," said Sanchez, a Miami native. "For me it's great that happened. I'd be just as happy for anyone else doing it."
Coghlan started the 11th with a sharp single that deflected off pitcher Brandon Lyon (0-1) for an infield hit before Sanchez pulled an 0-2 pitch over the head of left fielder J.D. Martinez, and Coghlan slid home without a throw.
The game was the Marlins' first at home since manager Ozzie Guillen began serving a five-game suspension for praising Fidel Castro. Guillen's remarks inflamed Cuban Americans, but there were no group demonstrations, and the stadium was about two-thirds full.
"People want to come to the ballpark. It's a brand new toy," interim manager Joey Cora said. "Second, they want to see a winner. You win games, they're going to come. I'm confident that's what is going to happen."
Announced attendance for only the second game in the 36,442-seat ballpark was 30,169.
Miami native Martinez hit the first home run in the ballpark, a two-run shot for Houston in the eighth inning off Edward Mujica to tie it 4-all. But several other long drives failed to clear the wall.
"It is a big place," Astros slugger Carlos Lee said. "We both hit the ball good today, and it didn't go nowhere. It's big for both teams."
With the retractable roof closed for the first time, Lee and teammate Chris Johnson flied out to the warning track in the fourth inning. Omar Infante had a warning-track flyout in the 10th, and the Marlins have yet to activate the animated home-run sculpture beyond the center field wall.
"So far it's a big, big, big, big ballpark," Cora said. "The ball Gaby hit, he crushed it. He'd better go to the weight room. It's going to be interesting to see what happens the rest of the year here, but right now it's playing big."
Miami newcomer Heath Bell, who blew his only save opportunity this season, survived a shaky ninth to keep the score tied. He retired the first two batters but then threw 13 consecutive balls to walk the bases loaded. Lee then tapped out on a check swing.
Ryan Webb (1-0) pitched a perfect 11th.
Marlins starter Ricky Nolasco needed 90 pitches to get through five innings but gave up only two runs. Houston's Lucas Harrell, coming off the best start of his career, lasted only four innings and allowed four runs.
The Marlins took a 4-2 lead into the eighth, but Jed Lowrie singled to start the inning, and Martinez homered into the nightclub seating area in left field.
"Words just can't describe it," said Martinez, who grew up a Marlins fans. "It was a great moment, but it would have been a lot better had we gotten the win."
Martinez also singled and scored, and he has at least one hit in all seven Astros games.
Infante's aggressiveness on the bases paid off for Miami in the third. He kept running from first on a grounder to third baseman Johnson, who ranged to his left and threw out the batter. When Infante kept going, Harrell scrambled to cover third, but the throw from first baseman Lee eluded him for an error, allowing the runner to score easily.
Infante, who began the day leading the NL in total bases, went 2 for 5 and is batting .367. Sanchez came into the game batting .125 but had three hits.
The game was the road opener for the Astros, who last year went 25-56 in away games, worst in the majors, and lost all four they played in Miami.
The Marlins, Miami Heat and Florida Panthers all played at home, the first time that has happened on the same day since April 14, 2002. ... Miami's Hanley Ramirez, off to a 4-for-30 start (.133), was on the field nearly four hours before the game hitting off a tee. ... Marlins SS Jose Reyes committed two errors, increasing his season total to three. He had 18 last year for the Mets. ... Astros manager Brad Mills doesn't think much of the colorful home-run sculpture but likes the ballpark's appearance otherwise. "It looks better in center field looking toward home plate," he said. "I'll leave it at that." ... Johnson tumbled headfirst into the first row to catch Emilio Bonifacio's pop foul.