Nigel Pearson stressed the Premier League has to be the priority for Watford and suggested the 3-3 FA Cup third round draw with Tranmere Rovers has reinforced his thinking about the squad currently at his disposal.

The Hornets appeared to be cruising through to the fourth round after goals from Tom Dele-Bashiru, Nathaniel Chalobah and Roberto Pereyra fired them into a 3-0 interval lead.

But a groin problem for Chalobah forced the Watford head coach into a change at the start of the second period and the game started to unravel for the hosts after VAR over-ruled the decision to disallow a Connor Jennings goal for offside.

Manny Monthe gave the visitors further hope when he scored a second and the League One side completed their incredible comeback three minutes from the end of normal time when substitute Paul Mullin converted a penalty, again following the intervention of VAR.

A late red card for Pereyra compounded a dismal second half for the Hornets, but Pearson made no apologies for the wholesale changes he made for the tie with his side embroiled in a relegation battle, stating he had learnt plenty from his side’s performance.

He said: “For me the priority has got to be the Premier League. I can’t sit in front of you and try to give you a feeling that everything is equal in terms of how we look at competitions. Unfortunately for us the FA Cup is not the priority.

“If we were in a more comfortable situation and had more players available, but we don’t at the minute, we have quite a lengthy injury list and I can’t afford as a football club to put ourselves into a situation where we go into the league programme with even fewer players available. It’s relatively simple like that as far as I’m concerned.

“I’ve got to make decisions based on what’s right for our season. Of course I would have liked to have gone through today and at half-time, coming in as we did, I would have expected us to see it through. But when you have an injury at half-time and then two players come off because they’ve got cramp it just shows you the situation we find ourselves in.

“[There are] Lessons to be learned and a good experience for those youngsters, but hopefully the take home message for them will be they’ve done alright today, but they also need to be technically and potentially good enough, they’ve got to be physically good enough as well.

“I’m sitting here today and, yes, I’m disappointed but I’m also in a position where I can say I’ve learnt quite a bit about players today and that’s really important too.”

Asked if the game had changed his thinking with the transfer window now open, he responded: “I think what it’s done is probably reinforced what we already know about the squad. Clearly having the number of options we have limits our options and I think one of the things that you’ve got to always look at is whether you know what your best side is.

“I think we’ve got a relatively settled side, we’ve got competition for places and I would have liked to have had the option to look at one or two players in slightly different positions today, but because of the substitutions that we had to make through injuries and players not being able to sustain performance meant we couldn’t look at what I would have liked to have looked at.”

Pereyra's late sending off saw Watford reduced to 10 men for the third game running. Pearson expressed his frustration about this but queried the apparent lack of VAR involvement in a tie which saw two Tranmere goals effectively come as the result of decisions from Stockley Park.

He said: “To have another sending off is really frustrating of course, and if we’re talking about VAR decisions I’m not sure that was even looked at.

"I’m told, I’ve not seen it and I’m certainly not looking for excuses or trying to have a pop at officials, but I’m told it’s petulant but that’s about it. It’s a bit frustrating that compounds on top of the result."