Prague (AFP) - Czech police said on Thursday (Nov 16) they had shelved investigations into last year's knife attack on two-time Wimbledon champion Petra Kvitova, which had put her career at stake.

"Despite extensive investigation, we have not managed to identify the attacker to date," detective Jan Lisicky told reporters.

"We shelved the case on Nov 8, 2017... but... if we find new facts, if we identify the attacker, we will immediately start criminal proceedings," he added.

The 27-year-old suffered career-threatening injuries to her playing left hand as she fought off a knife-wielding intruder at her home in the eastern Czech town of Prostejov in December 2016.

"She was in the wrong place at the wrong time. The attacker had no idea whom he was facing at first," said Lisicky.

Despite grim forecasts by doctors, who even warned she might lose her fingers, the 2011 and 2014 Wimbledon champion returned to the sport in time for the French Open in May.

Kvitova ended this year as world No. 29, having sunk from 11th at the end of 2016.

Since her return, she has won the Birmingham tournament in the run-up to Wimbledon and reached the US Open quarter-finals.

The former world number two and five-time Fed Cup winner has repeatedly called the incident "the past".

"She's looking ahead and she doesn't and will not look back at last year's events," her spokesman Karel Tejkal told the Czech news agency CTK on Thursday.