Coming into round 5 (of 10) of this year's Norway Chess tournament, Magnus Carlsen wasn't leading, but he had at least won every round. All his classical games were drawn, and he won both Armageddon games with White and drew both Armageddons with Black. Perhaps he would have drawn another Armageddon game with Black today, against Sergey Karjakin, but his erstwhile world championship match opponent "forgot" the script and won the classical game.
Carlsen had no problems in the opening, as he was well-prepared against the 7.Nd5 anti-Sveshnikov line Fabiano Caruana played against Carlsen in their 2018 world championship match. If anything, he had the advantage, and starting to feel frustrated by his lack of activity Karjakin uncorked the nice exchange sac with 23.Rac1 followed by 24.Rc6. Black should have said "Thanks, but no thanks", and kept the advantage. Once Carlsen grabbed the material Karjakin's position came to life, and soon he was much better. (One critical question, however, is what Karjakin would have played after 26...Rxa4. In the postgame interview with Judit Polgar, he gave a bizarre line: 27.Nc3 Rc4 28.Qxb5?? While watching this I wondered what was wrong with 28...Rxc3 - 29.bxc3 Bxf2+ followed by 30...Qxb5 is game over - and the answer is, of course, nothing; it's an elementary tactic. But I doubt that Karjakin really intended to do that; he was probably having a hard time remembering what he thought about the particular position, and may have mixed up his real plans with something he intended in some similar situation. Whatever the story, 26...Rxa4 would have been better than Carlsen's 26...Nd4.)
As noted before the long parenthetical, Karjakin was soon better, and while his subsequent play wasn't flawless, it was good enough and certainly better than his opponent's. There was one very nice finesse at the end, spotlighted by Karjakin after the game. After Carlsen's 47...Rxd3 the obvious move is 48.c7, but after 48...Rxb3! 49.c8Q Rxb5 Black has a fortress, and will draw by shuttling his rook back and forth from f5 to h5 and back again. Therefore, White played 48.b6! Rxb3 49.b7 Rb6 and now 50.h5! gxh5 51.Kh3 Rxc6 52.b8Q. Black is a pawn up, relative to the 48.c7 line, but what matters is that there's no fortress. The ...Rf5-h5-f5-h5 idea has been taken away, and Black won't have a ...Rg6-e6-g6-e6 fortress either, as White will take it away with f4-f5 at some point. Carlsen could have survived a while longer before his h- and f-pawns would have dropped, but as the technical degree of difficult for White was very low he gave up just two moves later.
Carlsen therefore not only failed to gain ground on Richard Rapport and Ian Nepomniachtchi, but fell behind Sergey Karjakin as well. He was even caught by Alireza Firouzja, who won one-sidedly after Aryan Tari met Firouzja's blunder with a bigger one of his own. Firouzja, with White, came out of the opening with an advantage, but by the time of 24...Qb6 the position was equal. Firouzja's 25.Kh1 was a serious error, giving Black a big, possibly winning advantage after 25...Bc4. Instead, Tari's 25...Ng6?? not only missed his chance, but left him with a nearly-lost position after 26.Qxe8+. Soon it was clearly lost, and Firouzja converted his plus with energetic play.
In the battle of the players in the top two spots, Rapport remained in first, but Nepo gained ground. Nepo as White obtained a small edge out of the opening, but wasn't able to convert it into something tangible and the game quickly petered out to a draw. The Armageddon game was another story. If the classical game featured solid, frankly dry play, the Armageddon game was anything but. Nepomniachtchi played 1.e4, Rapport played 1...d5 (why?), and more or less following theory was enough to give Nepo a big advantage, which was soon decisive. Rapport tried giving up the queen for a rook and a bishop and hopes of a fortress, but White had enough resources to break through and win.
At the halfway point, then, these are the standings. Remember, the scoring system is 3 wins for a classical win, no points for a classical loss, 1 point for a classical draw with an extra half point for winning the Armageddon game or drawing that game with Black. Thus Karjakin and Firouzja gained 3 points today, Tari and Carlsen got no points, Nepomniachtchi picked up a point and a half and Rapport a single point.
1. Rapport 9.5
2. Nepomniachtchi 8.5
3. Karjakin 7
4-5. Carlsen, Firouzja 6
6. Tari 3
Round 6 Pairings:
Carlsen (6) - Firouzja (6)
Karjakin (7) - Nepomniachtchi (8.5)
Rapport (9.5) - Tari (3)