Rafael Nadal reached the US Open final after a straight-sets win over Matteo Berrettini.
The Spanish second seed will face Russian Daniil Medvedev, who made his first grand slam final after beating Grigor Dimitrov, also in three.
Here, PA looks back at day 12 and ahead to day 13 at the US Open.
Shot of the day
Medvedev secures the point with this forehand winner on his way to earning a spot in the #USOpen finals in today's AI Highlight of the Day, insights by @IBM Watson. #IBMsports pic.twitter.com/NoKx2dzp75 — US Open Tennis (@usopen) September 6, 2019
Medvedev looked almost apologetic after this defensive forehand chop turned into a spectacular winner down the line.
Stat of the day
His maiden moment... 👏 Daniil Medvedev defeats Grigor Dimitrov 7-6(5), 6-4, 6-3 to reach the US Open final.@DaniilMedwed | #USOpen pic.twitter.com/P2Syi5cMYQ — US Open Tennis (@usopen) September 6, 2019
Medvedev is the third player, after Ivan Lendl and Andre Agassi, to reach the finals in Washington, Canada, Cincinnati and at the US Open in the same season.
Miss of the day
Berrettini's drop shot had been working well until, at set point in a first-set tie-break, he left one short. It might have been a different story had the Italian made it.
Quote of the day
Brit watch
Scotland's Gordon Reid went down in three sets 4-6 6-4 6-1 to France's Stephane Houdet in the quarter-finals of the men's wheelchair singles. In the wheelchair quad singles Andy Lapthorne had two match points against Australian Dylan Alcott but lost 0-6 7-6 (3) 6-3 in their round-robin match. Jamie Murray partners Bethanie Mattek-Sands will take part in the mixed doubles final on Saturday.
Serena's record attempt
Day 11 Notebook: Serena sets up final clash with Andreescu.https://t.co/RmAb2eY1q8 | #USOpen pic.twitter.com/fTODUbeJZZ — US Open Tennis (@usopen) September 6, 2019
Serena Williams will equal Magaret Court's all-time record of 24 grand slam victories if she beats Canadian teenager Bianca Andreescu in Saturday's final.
Order of play
Arthur Ashe Stadium:
Chan Hao-ching/Michael Venus v Bethanie Mattek-Sands/Jamie Murray
Bianca Andrescu v Serena Williams