Not so easy come, easy go for the Americans. Boards 1, 2 and 4 were drawn in their match with China, and all that remained was Alexander Onischuk trying to hold against Ding Liren. He was a pawn down in a rook ending, with all the pawns on one side, and with plenty of time on the clock. Normally, the draw should have been routine. Instead, after 54.g4, Onischuk rejected the obvious and sufficient 54...hxg4 for 54...Ra1. In fact this wasn't so bad, but it was the first step in a terrible direction. Onischuk may have missed White's next move, 55.g5, but this was only a trick. First off, the passive 55...Ra6 should be enough to hold the draw, but the best move was the obvious 55...fxg5! After 56.Rd6+ Kf5 57.Rd5+ Kg6 58.Rxg5+ (58.hxg5 h4 59.f4 h3 draws immediately) Kh6 Black has a tenable ending - in fact, it's drawn even without Black's h-pawn. Unfortunately, Onischuk rejected both 55...fxg5 and even 55...Ra6, uncorked the horrid 55...Rh1??, and was immediately and manifestly lost after 56.Rd6.
Ironically, the Russians won their match against Argentina in part by saving a similar ending. They won one game, when in a normal-looking Sicilian position Diego Flores played 17...b5?? against Sergey Karjakin. It's a perfectly normal kind of move; it's just that here, after 18.Nd5 Bxd5 19.exd5, Black was left to choose between positional capitulation (19...Ne7 20.c3 Nbxd5 21.Rxd5 Nxd5 22.Qxd5 etc.) and the loss of material (as in the game). Two games were drawn pretty routinely, and then it came down to Dmitry Jakovenko holding a pawn-down rook ending against Sandro Mareco.
Finally, there's the Armenian story. They followed inverse strategy, drawing with White and winning with Black on boards 1 and 3: Levon Aronian and Vladimir Akopian defeated Anish Giri and Ivan Sokolov, respectively.
Those are the leaders, and the only other team within a point is Ukraine. (They defeated the Azeris 2.5-1.5, with the sole decisive game coming on board 2, with Ruslan Ponomariov beating Eltaj Safarli.) There's one round to go, which comes after tomorrow's rest day, and then on Sunday the final top pairings are these:
Ukraine 16 - China 17
Hungary 15 - Armenia 17
Russia 17 - Germany 15
Poland 15 - USA 15
(Remember that 2-1-0 scoring is being used. All other teams have 14 points or fewer.) As the board 1 match will produce a team with at least 18 points, all the 15-pointers are shut out of the race for gold. But silver and bronze could come down to tiebreaks, and I'm not sure what the situation is there. According to reporting in Chess Today - and they weren't completely sure either - the first tiebreaker is the opponent's cumulative score, only then followed by board points. As that first tiebreaker is highly volatile, I'll leave analyzing that to my more industrious readers. Those who want to look up information of this sort may wish to investigate the official site and the full list of pairings.