The two playmakers were on the opposing teams as Chelsea played out a goalless draw with Manchester United at Old Trafford on Monday night.
Mata and Hazard played alongside each other at Chelsea before the Spaniard was deemed to be surplus to requirements by Jose Mourinho and was sold to United in January 2014.
However, it the pair are clearly close friends away from the game, if their latest posts on social media are anything to go by.
Hazard sent a message to Mata on Instagram on Tuesday morning – and the Spaniard duly replied with a post of his own later in the day.
Mata shared the picture above on the photo-sharing app and wrote: “Good to see you too my friend! Top Top Top player… #oldtimes #friend #football”
Monday’s draw extended United’s winless run in all competitions to eight games ahead of their home clash with Swansea on Saturday.
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