By then, he will know if his team have delivered their Olympic target of two gold medals, following the men's 10,000 metres final and the conclusion of the heptathlon the previous night.
The Games are depending on Jessica Ennis and Mo Farah fulfilling their destinies in front of 80,000 mostly partisan fans.
But Van Commenee also needs a couple of surprise medallists, and yesterday at the Diamond League meeting at Crystal Palace Christine Ohuruogu and Goldie Sayers provided reminders of their capabilities as they beat a world and Olympic champion respectively in their final events before the Games.
By the time of the last event, the women's 400m, it was hosing down, the sort of rain you don't go out in unless you must. For a young woman from Botswana, world champion Amantle Montsho, the starter's gun seemed a signal to scurry away, with the aim of getting indoors as soon as she could.
Ohuruogu won the world title in 2007 and Olympic gold in 2008 by running patient, strong-finishing races, the sort of last-gasp performances that get crowds on their feet. Injuries have blighted her running since 2008, but she has always retained a quiet assurance.
Thing is, when she is off the pace at halfway, it is impossible to know whether Ohuruogu is being patient, or simply off form. Yesterday, with 150m to run, Montsho held a five-metre lead and Ohuruogu was no better than fourth. Then came that moment when the crowd realised that Ohuruogu – who can see the Olympic Stadium from her parent's home in Newham – had something more to give.
Off the bend, as Montsho tired, the Londoner closed her down in the final strides. Very much the raining Olympic champion in these conditions: 50.42sec, her best for three years.
"It's getting there," Ohuruogu said, knowing that come the Olympics she will need to get well below 50sec, as she did in 2007 and 2008. "I am where I am," she shrugged. "I'm looking forward to the Games now."
If you bumped into Sayers in the street, you would not be able to guess her sport, never mind event. Slight, at 5ft 8in, and little more than 10st, she was public-school educated near Newmarket, so you might think she's a hockey player. On hearing her speak you could be forgiven for guessing she is in the eventing team.
Yesterday, with her first-round throw in the javelin, Sayers beat her four-year-old British record, reaching 66.17m. "About bloody time," she said, with good cause.
Sayers is 30 tomorrow. Hers has been a career of under-achievement, her fourth place at the Beijing Olympics when she threw her previous best, 65.75m, being the closest she has come to a medal at an international championship. The usual litany of injuries and bad luck applies.
Here, she was under no illusions about her Olympic medal prospects, or the need for typical UK conditions to play a part when she next competes. "I wouldn't mind if the whole British public did a rain dance for the next month," she said.
The cold and the rain is a great leveller, so when Sayers stepped up, her right shoulder still warm and supple, her arm snapped through in a rare, perfect connection. She backed that up with throws of 64.44 and 65.74 before she, too, complained of the dreich afternoon that had proved too much for Barbora Spotakova, the Beijing gold medallist.
"It's going to take more than that to medal for sure," Sayers said with refreshing realism. "But as the conditions got worse, it got quite treacherous at the end of the runway, so I knew they'd struggle to beat it. I would love to do something similar in the Olympic Stadium. I seem to like Olympic year, there's something special about it, I enjoy the spirit of it, and I feed off that."
Much of what passes between now and the Games is a phoney war played out in athletes' heads. Perri Shakes-Drayton will not lack confidence after her victory in the 400m hurdles on Friday, as she streaked home in 53.77sec.
Less pleased was Perth schoolteacher Eilidh Child, fifth in 55.91. Child's run was a long way off what she might need to progress beyond the semi-finals at the Games. "Not a great day at the office," she said, "but I took a couple of good scalps which I should be positive about."
Child at least competed. Phillips Idowu, a silver medallist in Beijing, pulled out of yesterday's triple jump citing a hip injury.
Van Commenee will therefore have taken comfort from seeing one of his two bankers come through unscathed, as Farah was there on Friday to offer a glimpse into what it takes to become a champion – an hour after the spectators had left the stands.
Farah's rousing 5000 had been the last event and the world champion covered the final two laps in a blood-pulsing 1min 54sec. He then went back on the track to run a hard 3000 rounded off with a set of 4x200m, each inside 26sec.
Olympic medals may be won and lost under the glare of flashbulbs and in front of packed stands, but it is when no-one is watching and the lights are down that champions are made.
GB hopefuls can take some positive signs from this Games warm-up event, says Steven Downes
Contextual targeting label: