In pure statistical terms, Houghton's third goal of the tournament meant Kelly Smith could afford to miss a second-half penalty as GB set up a last-eight clash with Canada.
The game was played in front of a British record 70,584 crowd for a women's Football match.
Meanwhile, Abby Wambach maintained reigning champions the USA's 100 per cent record in the competition with the defining moment of their narrow 1-0 victory over DPR Korea.
Wambach scored her 141st goal in her 185th appearance for her country at Manchester United's Old Trafford. It was enough to guarantee her side top spot in Group G, and a place in the quarter-finals against New Zealand.
South Africa battled their way to a first Olympic point while Japan advanced to the quarter-finals as Group F runners-up following a 0-0 draw at the Millennium Stadium.
Striker Kozue Ando and midfielder Asuna Tanaka wasted the best opportunities for Japan, who will take on Brazil for a place in the semi-finals.
Meanwhile, Elodie Thomis fired France into a quarter-final showdown with Sweden after a narrow 1-0 victory over Colombia.
The Lyon winger's early strike was enough to claim the points, although a resilient display by goalkeeper Sandra Sepulveda and a second-half Colombian fightback ensured the result remained in doubt until the final whistle.
France, inspired by the classy Louisa Necib, took the lead with just five minutes gone when the pacy Thomis got in behind full-back Natalia Ariza and calmly chipped the advancing Sepulveda.
Striker Melissa Tancredi claimed a double as Canada came from behind to snatch a precious 2-2 Group F draw with Sweden.
John Herdman's side trailed 2-0 to goals from Marie Hammarstrom and Sofia Jakobsson as the Swedes got off to a flying start.
But Tancredi reduced the deficit before the break and then claimed a later equaliser to ensure that both teams go through to the last eight.
New Zealand reached the quarter-finals after overcoming bottom-placed Cameroon 3-1 in Group E.