Grigor Dimitrov dropped 90 points, and that was enough to allow Alexander Zverev to slip past him and into the No. 4 spot this week.
But at this point, it’s a two-man race at the top, with Roger Federer and Rafael Nadal having nearly twice as many points as the current No. 3, Marin Cilic.
Federer, who added the indoor event in Rotterdam this week, needs a semi-final result to overtake Nadal and take back the No. 1 spot in the rankings for the first time since early November, 2012.
Will he do it? The (theoretical) last obstacle is countryman and friend Stan Wawrinka in the quarterfinals.
His first opponent will be qualifier Ruben Bemelmans of Belgium who, despite being on the tour 12 years has never faced Federer before.
On the Upswing
Stan Wawrinka (SUI): No. 15 ————–> No. 13 (Wawrinka begins his climb back up the rankings with a couple of spots after his last-minute entry into the Sofia event.
Andrey Rublev (RUS): No. 36 ————–> No. 34
Marius Copil (ROU): No. 93 ————–> No. 74 (At 27, Copil reached his first career ATP Tour final last week, and rises to a career best)
Roberto Carballes Baena (ESP): No. 107 ————–> No. 76 (At age 24, the Spaniard’s career is about to change. He went from the qualifying (one match) to the title in Quito last week, defeating Albert Ramos-Viñolas in the final and raising his ranking into a spot where his tournament selection is going to get a lot better).
Mirza Basic (BIH): No. 129 ————–> No. 77 (Bosnia represents, as the 26-year-old also reaches a career after winning three matches in qualifying and five in the main draw to earn his first career title in Sofia. He defeated some truly solid players during the week, too).
Thiago Monteiro (BRA): No. 118 ————–> No. 96 (The 23-year-old reached the semifinals in Quito).
Marcos Baghdatis (CYP): No. 123 ————–> No. 110
Andrej Martin (SVK): No. 156 ————–> No. 130
Jozef Kovalik (SVK): No. 187 ————–> No. 147 (From the qualifying to the semis in Sofia).
Jason Jung (TPE): No. 205 ————–> No. 155 (The California-born June wins the San Francisco Challenger to get close to his career high).
On the Downswing
Paolo Lorenzi (ITA): No. 46————–> No. 52 (And Lorenzi is not healthy; he pulled out of Buenos Aires this week)
Steve Darcis (BEL): No. 104 ————–> No. 121
Thomaz Bellucci (BRA): No. 108————-> No. 137 (Because of his drug suspension, Bellucci is starting his season late – and getting Victor Estrella Burgos in Quito for the fourth straight time was no picnic. He did qualify in Buenos Aires this week).
Dustin Brown (GER): No. 125 ————–> No. 138 (Brown was cruising against Nicolas Mahut in Montpellier last week when he got a sharp pain in his back and had to retire. A year ago at the same event, he injured his back as well, something that compromised his entire 2017 season)
Victor Estrella Burgos (DOM): No. 86 ————–> No. 139 (Estrella Burgos won the Ecuador Open the last three years, and it gave him enough ranking points to ensure entry into the Slams and thus, a decent living. He couldn’t make it a fourth time, and it sent his ranking tumbling and will have a big effect on the rest of 2018.