The goals have, however, dried up this season for Hazard, who scored his first league goals in Saturday's win over Bournemouth. The 25-year-old said in February that it would be "difficult to say no to (French side) Paris St Germain".
Hiddink told British media said Hazard was a "talented, high-quality player" who was suffering a frustratingly poor season because of injuries that have limited him to four goals in all competitions this year.
Hazard has been struggling with a hip ailment which forced him to sit out over a month of the campaign prior to Saturday's game against Bournemouth.
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"When he is there fully fit physically and mentally, then he is one of the best. I noticed that I saw him moving more, very light, very fresh (on Saturday)," Hiddink said.
"He was playing free with no doubt in his mind and any frustrations, so this was a good sign for me."
Hiddink said Hazard had several more years to go on his contract and "what I know (is), he is very happy with everything in Chelsea and around Chelsea. He is very important and if he is fit as he is today, (it is) showing."
Ninth-placed Chelsea will host title-chasing London rivals Tottenham Hotspur on May 2.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Mark Heinrich)
