It happened so suddenly that the Washington Whips goalkeeper Bobby Clark didn’t know what hit him. Los Angeles Wolves full-back Bobby Thomson drove in a dangerous cross that deflected off a defender’s leg, past Clark and into the goal. And just like that, the first and only United Soccer Association championship game was over. “It was the first time I had ever been involved in a sudden-death finish to a game and the finality was numbing,” Clark says five decades later.

The Wolves celebrated their achievement while the Whips tried to figure out what happened in a wild game that ended 6-5 at the Los Angeles Memorial Coliseum. Friday is the game’s 50th anniversary.

This match had everything. Goals galore, a hat-tricks for both sides – from LA’s David Burnside and Washington’s Frank Munro – a red card, a penalty save, a penalty scored and an own goal that decided matters six minutes into sudden-death extra-time. In his book about the league, Summer of ‘67, Ian Thomson called it “the greatest soccer final played on American soil”.

Fifty years on, it’s difficult to disagree. In 1967, the United States saw the dawn of a modern professional soccer era with two leagues – the National Professional Soccer League and the United Soccer Association (USA) – competing for attention from a public that did not care much about the beautiful game. Though it did not have the blessing of Fifa the National Professional Soccer League kicked off first, forcing the USA to move up its plans a year. Realizing it couldn’t form 12 new teams in a short amount of time, the USA brought in squads from abroad who were on their off-season in their home countries. For example, the Washington Whips were made up of players from Aberdeen, while the Los Angeles Wolves drew their squad from Wolverhampton Wanderers. The competition was separated into two divisions. Each team played 12 games over 46 days between the end of May and the start of July, with the division winners qualifying for the final.

For many, it was an adventure into the unknown. Clark was only 21 when he embarked on his American sojourn. “It wasn’t just we came to America, we were flying all over America,” Clark says. “We played a Dutch team in San Francisco [the Golden Gate Gales, drawn from ADO Den Haag], we played a Brazilian team [Bangu] in Houston, the Astrodome. We played Hibs [playing as Toronto City] in Toronto. In Scotland, you can pretty well get a bus and go whether you were going. To be flying to all the games, it was exciting. It was one of my fondest early-on memories of something that was amazingly special.”

Neither Clark or his team-mates saw themselves as pioneers. “We were pretty naive in those days,” he said. “There was no internet, there was not a lot of television channels in Scotland. We didn’t have a big exposure to America. The only America that we knew was through Hollywood. That was always exciting that you were going to a place where it was about film stars and Elvis Presley. Martin Buchan [a 19-year-old defender], he was a huge Elvis Presley fan. He had a great time collecting all these LPs when he was here.”

The Wolves finished with a two-point advantage over San Francisco in the Western Division. In the Eastern Division, the Whips trailed Cleveland until the final regular-season game. They grabbed a spot in the final, thanks in part to a game that was replayed after their opponents had used an illegal substitute.

On 14 July, LA hosted the final. Reserved seats cost $2 to $3, general admission was $1. An ad in the Los Angeles Times may have overhyped the game a little: “Soccer’s Super Match! The game of games in true World Cup class for the North American Championship! See your exciting Los Angeles Wolves – a team that has captured the heart of Los Angeles sports fans – battle for the championship of the United Soccer Association. Don’t miss this memorable major league match!”

Did it capture the heart? Not exactly. The Wolves attracted 40,660 fans in total for six home games. The LA Times had the memorable part right though. “They had some tremendous players,” Clark said. “You had Derek Dougan, who was one of the best center forwards, a Northern Ireland international. Big tall, skillful player up front.”

Clark rattles off other names, including winger Dave Wagstaffe, the first player to receive a red card in the English Football League, and Peter Knowles, who scored 101 goals in all competitions for Wolverhampton before retiring at 24 after becoming a Jehovah’s Witness and losing his playing ambition.

It should have been a low-scoring game – both teams had superb defences – but form was thrown out the window. Knowles’ 14-yard strike gave LA a third-minute lead, before the Whips equalized in the 21st minute through Jimmy Smith. Smith didn’t see the end of the match as he was sent off by referee Dick Giebner for kicking Wagstaffe 11 minutes later. “Losing Jimmy Smith, that was huge. He was a fantastic player. He played with Scotland. He went to Newcastle. He was one of the first £100,000 players to move; £100,000 doesn’t seem very much nowadays,” Clark says with a laugh.

Four goals in four frenzied minutes midway through the second-half left the game tied at 3-3. LA’s David Burnside completed his hat-trick in the 82nd minute to give his team the lead before the 19-year-old Frank Munro equalized in the 89th, forcing extra-time. LA took the lead again to make it 5-4 before Clark saved a penalty. Munro then converted a penalty of his own in stoppage time. There would be no penalty shoot-out, so the game went to sudden death.

“Our players were very tired but still trying to conjure a mini-miracle,” Clark says. It didn’t happen. Thomson’s deflected cross decided the game in the 126thminute.

During the postgame ceremonies, Wolves owner Jack Kent Cooke applauded the final. “There isn’t a writer in Hollywood, there never has been one, who could have written a script for the game tonight. Next year and the year after that and all the years to come, we’re going to be proudly privileged to bring you wonderful fans major league soccer here in Los Angeles. Thank you so much.”

As it turned out, major league soccer would have to wait a few decades.

The Wolves players returned to England $3,000 richer, not exactly a king’s ransom. The Whips, meanwhile, had to content themselves with a visit to nearby Disneyland the next day. The USA soon merged with the NPSL to form the NASL, which lasted until 1984.

Clark’s career was just about as long: he played for Aberdeen until 1982, and made 425 league appearances for the club as well as winning 17 caps for Scotland. He eventually got opportunities to take victory laps, winning the Scottish Cup and league during his career. Clark was destined to return the States for the second act of his career as a top college coach with Dartmouth for nine years. After coaching the New Zealand national team from 1994-96, Clark guided Stanford University from 1996-2000. He joined Notre Dame in 2001, directing the Fighting Irish to the 2013 NCAA Division I crown.

His playing and coaching career makes Clark one of a few individuals who has witnessed the growth of US professional soccer from its humble beginnings.

“It’s amazing how few people outside of expats really knew about soccer,” he says. “Nowadays, you don’t have to drive long before you’re passing a soccer field. Back then, if you saw one, you went, ‘Wow, that’s a soccer field.’

“It’s incredible how far it’s come. When we did some clinics with the Whips, kids, you’re showing them how to kick the ball. They would toe the ball rather than hit it with their in-step ... [Now] America can play with anyone. MLS is getting better and better. The crowds are there. I don’t know if it’s going to be in my time, but I can see it becoming one of the major leagues.”

And it was Clark and his colleagues who planted the seeds 50 years ago.