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 | Opponent | Venue | Result | Attendance | Scorers |
| --- | --- | --- | --- | --- | --- |
| 8 August 1998 | Bristol City | A | 2-2 | 13,729 | Murphy, Windass |
| 15 August 1998 | Wolverhampton Wanderers | H | 0-2 | 7,521 |  |
| 22 August 1998 | Crystal Palace | A | 0-2 | 14,827 |  |
| 29 August 1998 | Grimsby Town | H | 0-0 | 5,587 |  |
| 31 August 1998 | Barnsley | A | 0-1 | 15,328 |  |
| 6 September 1998 | Portsmouth | H | 3-0 | 6,626 | Marsh, Windass (2, 1 pen) |
| 9 September 1998 | Swindon Town | A | 1-4 | 8,305 | Banger |
| 12 September 1998 | Ipswich Town | H | 3-3 | 6,632 | Banger, Windass, Thomson |
| 19 September 1998 | Sunderland | A | 0-7 | 34,567 |  |
| 26 September 1998 | Queens Park Rangers | H | 4-1 | 7,489 | Beauchamp, Murphy, Thomson, Windass |
| 29 September 1998 | West Bromwich Albion | H | 3-0 | 7,437 | Beauchamp, Powell, Marsh |
| 3 October 1998 | Huddersfield Town | A | 0-2 | 10,968 |  |
| 10 October 1998 | Tranmere Rovers | H | 1-2 | 5,862 | Windass |
| 17 October 1998 | Bolton Wanderers | A | 1-1 | 17,064 | Thomson |
| 20 October 1998 | Bury | A | 0-1 | 3,436 |  |
| 24 October 1998 | Sheffield United | H | 0-2 | 6,586 |  |
| 31 October 1998 | Crewe Alexandra | H | 1-1 | 5,607 | Windass |
| 7 November 1998 | Watford | A | 0-2 | 10,137 |  |
| 14 November 1998 | Birmingham City | A | 1-0 | 18,216 | Murphy |
| 21 November 1998 | Port Vale | H | 2-1 | 5,964 | Windass (pen), Powell |
| 29 November 1998 | Norwich City | A | 3-1 | 17,851 | Wilsterman, Windass, Thomson |
| 5 December 1998 | Bradford City | H | 0-1 | 5,969 |  |
| 12 December 1998 | Birmingham City | H | 1-7 | 7,189 | Windass |
| 19 December 1998 | Stockport County | A | 0-2 | 6,500 |  |
| 26 December 1998 | Crystal Palace | H | 1-3 | 8,375 | Windass |
| 28 December 1998 | Portsmouth | A | 2-2 | 12,604 | Banger (2) |
| 9 January 1999 | Bristol City | H | 0-0 | 9,434 |  |
| 16 January 1999 | Grimsby Town | A | 0-1 | 6,626 |  |
| 30 January 1999 | Barnsley | H | 1-0 | 6,174 | Windass |
| 6 February 1999 | Wolverhampton Wanderers | A | 1-1 | 20,811 | Windass |
| 13 February 1999 | Swindon Town | H | 2-0 | 8,179 | Windass (2, 1 pen) |
| 20 February 1999 | Ipswich Town | A | 1-2 | 16,920 | Rémy |
| 27 February 1999 | Sunderland | H | 0-0 | 9,044 |  |
| 3 March 1999 | Queens Park Rangers | A | 0-1 | 9,040 |  |
| 6 March 1999 | West Bromwich Albion | A | 0-2 | 13,875 |  |
| 9 March 1999 | Huddersfield Town | H | 2-2 | 6,034 | Cook, Beauchamp |
| 13 March 1999 | Watford | H | 0-0 | 8,137 |  |
| 20 March 1999 | Crewe Alexandra | A | 1-3 | 4,791 | Thomson |
| 26 March 1999 | Sheffield United | A | 2-1 | 14,115 | Thomson, Banger |
| 3 April 1999 | Bolton Wanderers | H | 0-0 | 7,547 |  |
| 5 April 1999 | Tranmere Rovers | A | 2-2 | 7,837 | Weatherstone, Gilchrist |
| 10 April 1999 | Bury | H | 0-1 | 6,358 |  |
| 17 April 1999 | Port Vale | A | 0-1 | 7,393 |  |
| 24 April 1999 | Norwich City | H | 2-4 | 7,345 | Wilsterman, Francis |
| 1 May 1999 | Bradford City | A | 0-0 | 15,064 |  |
| 9 May 1999 | Stockport County | H | 5-0 | 6,830 | Gilchrist, Powell, Beauchamp, Murphy, Thomson |
Question:
what was the first opponent oxford united f.c. defeated during the season?
Answer:
Portsmouth