A string of disappointing results left Watford with little alternative but to part company with Aidy Boothroyd earlier this week leaving Malky Mackay in charge for the double header against the Swans.
The Hornets are at the Liberty Stadium on both Sunday (league) and Tuesday (Carling Cup) with the Swans instilled as favourites for both clashes – helped by the unbeaten home record to date this season.
But Martinez is taking nothing for granted and told the Evening Post “It’s very unfortunate to see Aidy Boothroyd leave his job after what he has done for Watford
“This is a very tight division where anyone can beat anyone else and there is only a third of the campaign gone.
“From our point of view it’s unfortunate too.
“You don’t want to be involved in the middle of all these things but we have to be ready now for a completely different Watford side from the one that played last weekend.
“I’m not saying that in the long term Aidy Boothroyd’s departure will benefit Watford because that will depend on all sorts of factors, but in the short term you are going to get a reaction from the players.
“It’s a fresh start for them and probably the first three or four games are the wrong time to play Watford.
“I don’t expect too much to change in terms of the way they play because the new people in charge do not have a lot of time.
“But the players will be keen to make an impression. They will be fighting to get a result and in a sense we have to expect the unexpected.”