It was nearly a once in a lifetime event.  Venus crossed the path of the sun in front of the Earth.  And Roger Federer and Novak Djokovic were nearly both upset on the same day at roughly the same time.

French Open organizers were criticized for scheduling two big matches at the same time, though given how long both these matches went, it may have been a good idea for scheduling if not necessarily for the fans.

Roger Federer had been in this situation before.  In 2009, when Federer was given an opportunity of a lifetime–the early exit by Rafael Nadal by the hands of Robin Soderling, he faced an ascendant Juan Martin del Potro who had been on a steady climb.  Federer had yet to lose to del Potro, but in this match, he was pushed to a fifth set, and finally won it.  He would later lose to del Potro in the finals of the US Open before an injury that required surgery took del Potro off the tour for most of 2010.  Although del Potro would play most of 2011 and win tournaments, he knew he wasn’t quite ready to beat Roger Federer.  Indeed, he’s lost to him several times in 2012.

del Potro took the first two sets in 63, 76.  The second set ended rather testily as a fan yelled out on a ball that did not go out and Federer missed the ball.  Federer screamed “Shut up!” betraying a rage that’s rarely seen by the placid Swiss champ.

Despite the danger of the situation, the next three sets went so decisively Federer’s way, one has to wonder what happened.  del Potro’s knee had been bandaged up.  Earlier in the tournament, he said he would work through the pain.  Although he didn’t seem severely hampered, Federer nonetheless took control of the match and took the next three sets, 62, 60, 63.

Novak Djokovic was in more dire straits.  He won the first set handily, 61, but Tsonga came back to take the next two sets, 75, 75.  In the fourth set, Tsonga was Djokovic down double break point which were also match points, but Djokovic came with a brave shot at net, and held serve.  He would save another two match points down break point (twice) and 56 down. Then, one more match point as he pushed the match into tiebreak, one that Djokovic barely won 8-6.

Tsonga’s desire must have deflated because Djokovic took the fifth set 61 and kept alive his opportunity to hold four consecutive Slams.  There, he’ll meet the man who beat him last year in four sets.  Federer will have reached yet another Slam semi, his 29th so far.  He has not reached the finals since the French Open, and not won a Slam title since the 2010 Australian Open, so he’ll be eager to take Djokovic out once again as Djokovic has done to him in the US Open the last two years.

Tomorrow, Murray will take on Ferrer.  Ferrer is the one on a hot streak, but Murray has fared better in Slams.  Can Murray beat a guy who doesn’t beat himself?  And can Almagro make any more of an impression against Nadal than his hapless opponents have?  Can he stop Nadal from reaching his 7th French Open title breaking a tie he holds with Borg?

In the meanwhile, there’s still a few more hours before Venus completely crosses the sun from the perspective of the Earth.