He played great, for a backup who is not a starter level player. Lets look at his game by game numbers just to prove that really quickly.
Eagles: 18-38, 181 yds, 1TD, 3 INTs, 4.8 Y/PA (yards per attempt)
Rams: 10-16 , 102yds, 6.4 yards per attempt
Washington: 15-27 223 yards, 2TDs, 8.3 Y/PA
Giants: 21-31, 215 yards, 1 TD, 6.9 Y/PA
Bengals: 19-31, 235 yards, 1 TD, 7.6 Y/PA
So lets take out great immediately because you would not call a single one of those lines great. The only game in that bunch that would you say is good is the Giants line and even then the limited yards quickly shows his limitations pushing it down the field. The illusion that he played great is one of the funniest things to me when the games were televised and we could watch them and then after look at the numbers.