Watford and Southampton both remain winless in the Premier League after playing out a 0-0 draw at Vicarage Road on Sunday.
Quique Sanchez Flores' men now have three draws from as many games on their return to the top flight, after Southampton seemed to show the hallmarks of a team given a thorough midweek workout in the UEFA Europa League.
Ronald Koeman's side were held 1-1 by Midtjylland on Thursday and were unable to break down a well-drilled Watford, who had the better of the chances.
A frustrating afternoon for Saints - who named Victor Wanyama in their side amid speculation over his future - was made worse by the injury-enforced first-half withdrawal of Sadio Mane.
Replacement Shane Long offered something of a threat in Mane's stead but the likes of Ikechi Anya, Troy Deeney and debutant Alessandro Diamanti proved more dangerous for the hosts.
The Scotland international was key to the hosts' bright start, although Southampton had the first real chance courtesy of Mane and his blistering pace.
Koeman's side grew into the contest but their momentum was checked when Mane was forced off 25 minutes in having been involved in two robust challenges.
The lively Anya drilled a dangerous ball across goal, yet Ighalo was unable to make contact.
Flores handed Diamanti a Watford debut at the start of the second half, but it was Southampton who threatened early, Graziano Pelle's strike and a flicked header from Long testing Heurelho Gomes.
As Watford responded, Diamanti offered a glimpse of his quality with a cross that narrowly evaded Deeney before Capoue spurned a glorious opportunity to break the deadlock.
The Frenchman could only angle Deeney's flick-on over the crossbar, while the best Southampton could muster at the other end came courtesy of long-range efforts from Wanyama and Cedric Soares.
While the game opened up late on, there was to be no winner, although Watford could take heart from another competitive showing as Southampton's sluggish start to the campaign continued.
