08/02/2012 08:28 EDT | Updated 10/02/2012 05:12 EDT

Athletics starts late in Olympics, but Ennis there to light it up from first morning

LONDON - It won't take long for the British crowd to warm up when the London Games athletics competition opens Friday at the Olympic stadium.

Five minutes into the program, Jessica Ennis and other heptathletes will line up for the 100-meter hurdles, the first of seven disciplines in the event.

Ennis, born in Sheffield and one of Britain's best chance for an athletics gold, will have to shoot out of the blocks fastest since the sprint hurdles is one of her best events in the two-day competition. She will hope to build an early lead over her rivals, world champion Tatyana Chernova of Russia and defending champion Natallia Dobrynska of Ukraine.

Add the crowds, the nation's expectations, and it could all become a bit much for Ennis.

"I'm trying not to think about it too much, because that again adds more pressure," Ennis said. The heptathlon will also provide a fitting entree for the Bolt-Blake sprint mania on the weekend.

The opening day will also have the finals of the men's shot put and the women's 10,000. On top of that, the U.S.-Jamaica sprint rivalry will kick off with the heats in the women's 100. As in Beijing four years ago, it is expected to be the defining story of the games.

It was a wipeout four years ago, with Jamaicans Usain Bolt and Veronica Cambell-Brown in starring roles. Now, the Americans are bent to restore their historical dominance.

"The Americans and Jamaicans have been going back and forth for several years, especially in the sprints. We do enjoy racing against each other because we are very competitive," Campbell-Brown said.

Campbell-Brown will be going for her third 200 Olympic title in a row next week, but lines up with defending champion Shelly-Ann Fraser-Pryce to face Americans Carmelita Jeter and Allyson Felix in the 100 heats Friday evening.

That should be a real U.S-Jamaica battle come Saturday's final, while everyone expects Sunday's men's final to be a showdown between Bolt and fellow Jamaican Yohan Blake.

Tyson Gay and 2004 Olympic champion Justin Gatlin hope they will be in it for more than just a scramble for bronze.

"It's important for the Americans to get back on top in the sprints," said Gay.

By Friday night, the U.S. team could already have its first gold in hand, considering its strength in depth in the shot put with Christian Cantwell, Reese Hoffa and Ryan Whiting. Since Randy Barnes' gold at the 1996 Atlanta Games though, the title has escaped the Americans. And this time, the main threat comes from German David Storl. At 22, he already is world and European champion and has always peaked when it really matters.

The Jamaica vs. United States rivalry in the sprints translates to Kenya vs. Ethiopia in the long distance races and that one starts with the women's 10,000 in Friday's last event.

It will pit Ethiopia's Tirunesh Dibaba, seeking to become the first repeat champion in the race, against world champion Vivian Cheruiyot of Kenya.

Both have a long-distance double on their mind. Dibaba already did it in Beijing four years ago and Cheruiyot clinched both 5,000 and 10,000 at last year's world championships in Daegu.