"Danny is fully focused on everything that's going on here at the moment," Mackay told BBC Three Counties Radio.
"We've got one intention and that's to win on Saturday and to keep going on and keep trying to win as many games between now and the end of the season."
Graham, in his second season for the Hornets following his arrival from Carlisle, has sparked interest after an impressive campaign so far which has seen him tally 18 goals in all competitions.
He has found the target 32 times in 76 Watford appearances and should he find the net against Cardiff on Saturday, he will become the first ever Hornet to score in eight consecutive games.
For me Taylor and Mutch are musts, they are huge parts of our season to date and should come back to finish the job
wfcthroughandthrough
His form has somewhat overshadowed the contribution of his 19-year-old strike partner Marvin Sordell.
The academy product has five goals in his last five games and Mackay feels he should share the plaudits with his fellow frontman.
"We knew we had to nurture him through, that's why we put him out to Tranmere last season," Mackay said.
"And there's a lot of belief within that young lad to go and be a top player.
"I'm going to make sure he works hard at his game to bring out all that potential.
"He's become a real threat at Championship level and a real thorn in the side of teams."
Mackay has moved to bolster his attacking options with Aston Villa striker Andreas Wiemann and Tottenham winger Andros Townsend arriving on loan.
But he has not ruled out any more additions, with Middlesbrough's Andrew Taylor and Birmingham's Jordan Mutch, who were both on loan at Vicarage Road earlier in the season, still on his radar.
"We're still talking to Middlesbrough about trying to get Andrew Taylor back here," Mackay continued.
"And with Jordan Mutch's situation at Birmingham, we're still talking to them about trying to get him back."
Source: BBC Sport
Source: BBC Sport