Cornet played at the Hopman Cup, and placed third in her group, partnering Gilles Simon. She defeated Su-Wei Hsieh of Chinese Taipei and Italian Flavia Pennetta. She then lost to Russia's Dinara Safina, 6-3, 6-2.
2-6, 6-2, 5-7. This was her third loss to the Russian already that year.
Cornet began the season at the Medibank International where she defeated 7th seed Nadia Petrova and Alisa Kleybanova before losing to second seed and eventual finalist Dinara Safina in the quarterfinals 6-3, 6-4. Cornet entered the Australian Open as the fifteenth seed, easily winning her two matches. In the third round, she dropped a set against Daniela Hantuchova, but advanced regardless. In the fourth round, she held two match points against Dinara Safina, but was eventually ousted
Cornet then took part in the Open GDF Suez in Paris. Seeded fifth, she defeated Latvian qualifier Anastasija Sevastova in the first round and went on to again defeat Hantuchová in three tight sets in the second round. She was then defeated by the number 2 seed Jelena Janković in the quarter-finals, 7-5, 4-6, 4-6.
Cornet at the 2009 Wimbledon Championships.
Despite having an impressive first month of the year, Cornet's results began to slide. She lost her two matches to Francesca Schiavone and Flavia Pennetta in the Fed Cup, playing for France. Her best result in her next seven tournaments were third round showings in Dubai and Miami. She would lose another two matches in the Fed Cup Play-offs, to Daniela Hantuchova and Dominika Cibulkova.
Cornet fell in the early rounds in both the French Open and Wimbledon, continuing a dismal 2009 tennis season.
Cornet was then defeated in the early rounds in Budapest and Palermo. After months of early losses, Cornet had a promising showing in Bad Gastein, advancing to the semifinals before losing to Ioana Raluca Olaru 6-3, 5-7, 3-6, which Cornet had a 5-4 lead and serve for closing the match in the second set.
