Mark Gardner pitched nine no-hit innings in a July 26, game before losing 1–0 in the 10th inning to the Los Angeles Dodgers. Two days later, also in Los Angeles, Dennis Martínez achieved a rare feat, throwing the 13th official perfect game in Major League Baseball history (based on MLB's 1991 redefinition of a perfect game), winning 2–0. Dave Van Horne's iconic call of "El Presidente, El Perfecto!" following the final out became a hallmark of Expos lore. Martinez's catcher, Ron Hassey, also caught Len Barker's perfect game ten years earlier and remains the only player to catch two perfect games in MLB history. The euphoria of the pitching feats did not last, as the Expos were rendered homeless for the final month of the season after a 50-ton beam collapsed from Olympic Stadium's structure and fell nine metres onto a public concourse hours before a motocross event on September 13. The Expos hinted that they would have to open the 1992 season elsewhere unless Olympic Stadium was certified safe. While the stadium itself was given a clean bill of health by engineers in November, it took longer to get one for the roof since it had been badly ripped in a June windstorm. Ultimately, it was decided to keep the roof closed at all times; it had only been opened 88 times in a little more than four years.