Here is one way saving grace and common grace relate: deed ministry, which is essential to the testimony of the gospel, often requires common grace in order to be done well.
Hence, it is unwise as Christians to downplay secular wisdom (common grace). Secular wisdom is not the gospel. But it is God’s will that Christians be wise both in a saving sense (Proverbs 11:30) and in relation to how to live well in this world (Proverbs 6:6-8).