West Bromwich Albion drew with Aston Villa on Friday.
Jay Rodriguez scored the equaliser for the Baggies in injury time, with the ball going in off his arm.
Watford goalkeeper Foster was following the match, and the 35-year-old former Manchester United man was pleased to see Rodriguez get the equaliser.
The former Birmingham City goalkeeper joined Watford from West Brom in the summer transfer window for a fee reported by The Daily Mail to be worth £4 million.
Over the course of the 90 minutes at The Hawthorns on Friday evening, hosts West Brom had 52% of the possession, took 14 shots of which six were on target, and earned five corners, according to BBC Sport.
Visitors Villa had 48% of the possession, took 14 shots of which seven were on target, and earned two corners, according to BBC Sport.