Magnus Carlsen’s scintillating performance at five-minute blitz last weekend is assured of a place in the record books. The world champion totalled 14.5/18, finished 4.5 points clear of his nearest elite rivals in the Grand Tour event at Leuven, Belgium, and registered a 3,018 performance rating, the first time the 3,000 mark has been surpassed in competition.

Carlsen won his games in a variety of styles, ranging from fantastic sacrifices a la Mikhail Tal to solid conversions of extra pawns. Garry Kasparov called it “phenomenal”. Only Bobby Fischer’s crushing victory at the world blitz in 1970, where he also outclassed a star field, stands comparison.

The problem is that this elegant tour de force did nothing, except as a confidence booster, to solve Carlsen’s shrinking lead over his rivals in classical slow chess, which is what really counts. Blitz games are rated separately and do not help the 26-year-old Norwegian’s slim margin of a dozen points in the classical rankings. His No1 status remains under threat, and will be tested in his next classical event, the Sinquefield Cup at St Louis, starting on 31 July.

Meanwhile the third leg of four of the Fide Grand Prix is under way this weekend in Geneva. After the final leg in Majorca the two overall winners will qualify for the eight-player 2018 candidates tournament which decides the challenger for Carlsen’s global crown. The legs in Sharjah and Moscow have already thinned out the contenders, and at present Shak Mamedyarov of Azerbaijan and Alex Grischuk of Russia, who play in Geneva, plus Maxime Vachier-Lagrave of France and Ding Liren of China, whose final event is Majorca, have the race between them.

The potential joker in the pack is Armenia’s Levon Aronian, impressive winner of elite tournaments earlier this year at Karlsruhe and Stavanger. Aronian failed at Sharjah, and needs two big results, probably including at least one first place, to climb back into contention at Geneva and Majorca. Michael Adams, the England No1, is also in the Geneva field but the 45-year-old Cornishman was an also-ran in both Sharjah and Moscow.

Closer to home, much closer, on Saturday the site of the Guardian’s offices welcomes the fifth annual DeMontford Bell Kings Place Festival, London’s leading one-day event. The organiser, Adam Raoof, reports a full house of 330 players plus a waiting list.

England’s Olympiad grandmasters David Howell and Luke McShane are the top seeds contending for the £1,000 first prize in the Open. The Guardian’s Stephen Moss, whose acclaimed chess book The Rookie will be released on 13 July as a Bloomsbury paperback at £8.99, will also play in the event and present the prizes, including signed copies of his book.

Russia’s Ian Nepomniachtchi tried to surprise the world champion at Leuven with the rare Centre Game 2 d4 and 3 Qxd4, but soon spoilt it by 8 Qf4? which gives Black an extra move compared with the immediate 8 Qg3. White was clearly worse by move 15, and in desperation accepted Carlsen’s knight sacrifce at b4 which left the white king with scanty protection. If White tries 17 Kb1 Ra1+! 18 Kxa1 Bxc2 leads to mate, while in the game 18...Qxb2! finished it. Nepo resigned in the face of 20 Kxd1 Qa1+ 21 Kd2 Qe1 mate.

Ian Nepomniachtchi v Magnus Carlsen

1 e4 e5 2 d4 exd4 3 Qxd4 Nc6 4 Qe3 Bb4+ 5 Nc3 Nf6 6 Bd2 O-O 7 O-O-O Re8 8 Qf4? Bxc3 9 Bxc3 Rxe4 10 Qg3 d5 11 f3 Re8 12 Ne2 a5 13 Nf4 Nb4 14 Bxf6 Qxf6 15 a3?! Bf5! 16 axb4? axb4 17 Nxd5 Ra1+ 18 Kd2 Qxb2! 19 Qxc7 Rxd1+ 0-1

3502 The game ended 1...Qh6?? 2 Qxf7+! and mates.