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 | Round | Opponent | Venue | Result | Attendance |
| --- | --- | --- | --- | --- | --- |
| 17 September 1998 | R1 | Helsingborg | H | 1-0 | 17714.0 |
| 1 October 1998 | R1 | Helsingborg | A | 0-0 | 12348.0 |
| 22 October 1998 | R2 | Copenhagen | H | 1-1 | 21207.0 |
| 5 November 1998 | R2 | Copenhagen | A | 1-0 | 24188.0 |
| 4 March 1999 | QF | Vålerenga | H | 3-0 | 34177.0 |
| 18 March 1999 | QF | Vålerenga | A | 3-2 | 17936.0 |
| 8 April 1999 | SF | Mallorca | H | 1-1 | 35524.0 |
| 22 April 1999 | SF | Mallorca | A | 0-1 | 18848.0 |
Question:
What is Opponent, when Date is 17 September 1998?
Answer:
Helsingborg