Ireland's Annelise Murphy is in with a medal shout in the Laser Radial class with only one point separating the top four.
Murphy appears to be in a contest with Xu Lijia, Marit Bouwmeester and Evi Van Acker for a place on the podium at Weymouth Bay on Monday.
Olympic debutante Murphy has promised to attack from the off in the medal race and is currently in joint bronze medal position.
“It was pretty hard out there,” said Ireland’s Murphy, who finished third and seventh today. “Everybody has been having good races and average races so between us top four it is pretty tight.
“I am just going to approach the medal race like any other race and attack it. Hopefully I can take advantage of that.
“I don’t think we’ll be able to match race each other as we’re so tight on points. It is going to be a good race.”
In London, Paddy Barnes claimed to be the first boxer to tweet news of his victory from inside the Olympic ring after reaching the last 16 of the light-flyweight competition with a 15-10 win over Cameroon’s Thomas Essomba.
The Belfast 25-year-old told his 8,000 followers: “Job done from the Olympic ring. Paddy Barnes – bringing you closer to the action,” later adding: “Think I’m the first boxer to tweet from inside (the) ring.”
Triathlete Aileen Morrison finished 43rd with a time of two hours eight minutes and 16 seconds, more than eight minutes behind Nicola Spirig who won gold for Switzerland.
It was an eventful race for the Irishwoman who crashed on her bicycle near Buckingham Palace but still finished.
“You have good races and bad races all the time and unfortunately today was one of the not so good races. I didn’t have the swim I wanted, I was left chasing on the bike,” she said.
“I thought I was doing okay and then on the first lap on the bike I came down. It was slippy and you’re putting in every effort you can. We were never going to catch up.”
There was disappointment in the Olympics Stadium for pole vaulter Tori Pena who failed to qualify, unable to clear the bar.
Steeplechaser Stephanie Reilly came ninth in heat two in a race won by Ethiopia’s Sofia Assefa and thus misses the final over 3000m.
Ireland’s race walker Rob Heffernan had to settle for ninth place in the 20km event.
Heffernan crossed the line on The Mall one minute and 32 seconds behind the race winner, Chen Ding of China but will be encouraged as he considers the 50km race his speciality.
In the 400m, Joanne Cuddihy was 16th fastest in the semi-finals after a fifth-placed finish behind Sanya Richards-Ross and will miss the final.
Cyclist Martyn Irvine admits his chances of a medal in the men’s omnium are over but has vowed to put in an improved performance tomorrow.
The 27-year-old from Newtownards had a disappointing day in the velodrome, closing in 10th position after three of the competition’s six events.
He started off with a ninth-placed finish in the 250m flying lap, clocking 13.504 seconds, and was then sixth with a score of 47 in the points race.
But his podium ambitions took a hammering when he was the fourth rider out of 18 to exit out in the elimination race.
“It was a reality kick,” he said.
At Eton Dorney, rower Sanita Puspure came 14th in the women’s singles sculls with some consolation in winning the c final.
Equestrian specialists Cian O’Connor and Billy Twomey are through to the next round of the show jumping competition.
Back in Dorset, Ger Owens and Scott Flanigan were 15th and 22nd in races five and six and lie 24th in the standings with five races including the medal race to come.
In the Laser, James Espey was 25th and 35th to lie 37th ahead of the medal race.