Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Date | Championship | Location | Category | Surface | Prev. result | Prev. points | New points | Outcome |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 29 December 2013–\n5 January 2014 | Brisbane International | Brisbane (AUS) | WTA Premier | Hard | SF | 200 | 305 | Final\nLost to Serena Williams 4–6, 5–7 |
| 14 January 2014–\n27 January 2014 | Australian Open | Melbourne (AUS) | Grand Slam | Hard | W | 2000 | 430 | Quarter-finals\nLost to Agnieszka Radwańska 1–6, 7–5, 0–6 |
| 10 February 2014–\n16 February 2014 | Qatar Total Open | Doha (QAT) | WTA Premier 5 | Hard | W | 900 | 0 | Withdrew due to left foot injury |
| 3 March 2014–\n16 March 2014 | Indian Wells | Indian Wells (USA) | WTA Premier Mandatory | Hard | QF | 250 | 45 | Second round\nLost to Lauren Davis 0–6, 6–7(2–7) |
| 17 March 2013–\n30 March 2014 | Sony Open Tennis | Miami (USA) | WTA Premier Mandatory | Hard | DNP | 0 | 0 | Withdrew due to left foot injury |
| 5 May 2014–\n11 May 2014 | Mutua Madrid Masters | Madrid (ESP) | WTA Premier Mandatory | Clay | 2R | 60 | TBD | Pending |
| 12 May 2014–\n18 May 2014 | Internazionali BNL d'Italia | Rome (ITA) | WTA Premier 5 | Clay | F | 700 | TBD | Pending |
| 25 May 2014–\n8 June 2014 | French Open | Paris (FRA) | Grand Slam | Clay | SF | 900 | TBD | Pending |
| 23 June 2014–\n6 July 2014 | Wimbledon | London (GBR) | Grand Slam | Grass | 2R | 100 | TBD | Pending |
| 4 August 2014–\n10 August 2014 | Rogers Cup | Toronto (CAN) | WTA Premier 5 | Hard | DNP | 0 | TBD | Pending |
| 11 August 2014–\n17 August 2014 | Western and Southern Open | Cincinnati (USA) | WTA Premier 5 | Hard | W | 900 | TBD | Pending |
| 25 August 2014–\n8 September 2014 | US Open | New York (USA) | Grand Slam | Hard | F | 1400 | TBD | Pending |
| 22 September 2014–\n27 September 2014 | Toray Pan Pacific Open | Wuhan (CHN) | WTA Premier 5 | Hard | 2R | 60 | TBD | Pending |
| 27 September 2014–\n5 October 2014 | China Open | Beijing (CHN) | WTA Premier Mandatory | Hard | 1R | 5 | TBD | Pending |
| 20 October 2013–\n26 October 2014 | WTA Tour Championships | Singapore (SIN) | WTA Tour Championships | Hard (i) | RR | 400 | TBD | Pending |
Question:
what was the latest championship to be played in the grand slam category?
Answer:
US Open