Watford manager Walter Mazzarri is sweating on the fitness of record signing Isaac Success ahead of his side<span><span>&rsquo;s clash with Southampton on the opening day of the season in the Premier League.<br /><br />The Nigeria youth international will discover later today if he has a chance of playing against the Saints, having missed training for most part of this week due to a muscular injury. <br /><br /></span></span><span><span><span><span>&ldquo;Success has a slight knock. He did not train on Monday and Tuesday,</span></span></span></span><span><span><span><span><span><span><span>&rdquo; a source told <b>allnigeriasoccer.com</b>.</span></span></span> <br /><br /></span></span></span></span><span><span><span><span><span><span><span><span>&ldquo;</span></span></span></span>He has insisted that he can play with the injury and will know if he is the 18-man squad later today.</span></span></span></span><span><span><span><span><span><span><span>&rdquo;<br /><br />For the forthcoming season, the former Granada star will suit up with the iconic number ten jersey at Watford. <br /><br />Isaac Success penned a multi-year deal with the Vicarage Stadium outfit this summer. <br /><br />Ifeanyi Emmanuel <br /></span></span></span><br /></span></span></span></span>