25-year-old forward Ighalo moved to Vicarage Road at the beginning of this season, joining on a season-long loan from sister club Udinese.
Making his debut in the League Cup, Ighalo is currently on a consistent run in the first-team with the absence of captain Troy Deeney, whose injury has left him out of action for a number of weeks.
Starting his second straight game on Tuesday night, Ighalo hit the crossbar early on against Brentford, before being taken down in the box and being awarded a penalty.
Having been fouled, the former Nigerian youth international was the man to step up for the spot-kick, and, despite missing at the first attempt, he followed up and netted the rebound. It was his first goal in Watford colours, and Ighalo told Nigerian media outlet sl10.ng that he was delighted to open his account for the Hertfordshire side.
The forward said: ''I'm the one that won the penalty for Watford after I was brought down. I wanted to take the penalty, so I score and build my confidence.
''Though the goalkeeper saved the kick, I was lucky that he punched the ball to my direction and I was lucky to score. A goal is a goal and I take it.’'
The 2-1 victory started by Ighalo’s strike took the club into third place, level with Norwich and Nottingham Forest at the top of the table. Brighton and Hove Albion travel to Vicarage Road on Saturday, and Ighalo is keen on continuing the good start enjoyed by the Hornets, with a long season still ahead.
He added: 'What I know about Watford is that we always start well, and I hope we finish well this season. The League is very tough, you only have to look at the standings, three teams have 18 points.
''It is very close, so we have to keep on winning home and away. I pray as we started well, we'll end well. We have 36 more matches to play excluding cup games; the season is very long.
''We'll take it game by game and see if we'll achieve our target at the end of the season."